Nitrogen source-dependent capsule induction in human-pathogenic cryptococcus species.

PubMed

Frazzitta, Aubrey E; Vora, Haily; Price, Michael S; Tenor, Jennifer L; Betancourt-Quiroz, Marisol; Toffaletti, Dena L; Cheng, Nan; Perfect, John R

2013-11-01

Cryptococcus neoformans and C. gattii cause meningoencephalitis and are an increasing human health threat. These pathogenic Cryptococcus species are neurotropic and persist in the cerebrospinal fluid (CSF) of the mammalian host during infection. In order to survive in the host, pathogenic fungi must procure nutrients, such as carbon and nitrogen, from the CSF. To enhance our understanding of nutrient acquisition during central nervous system infection by Cryptococcus species, we examined the utilization of nitrogen sources available in CSF. We screened for the growth and capsule production of 817 global environmental and clinical isolates on various sources of nitrogen. Both environmental and clinical strains grew robustly on uric acid, Casamino Acids, creatinine, and asparagine as sole nitrogen sources. Urea induced the greatest magnitude of capsule induction. This induction was greater in Cryptococcus gattii than in C. neoformans. We confirmed the ability of nonpreferred nitrogen sources to increase capsule production in pathogenic species of Cryptococcus. Since urea is metabolized to ammonia and CO(2) (a known signal for capsule induction), we examined urea metabolism mutants for their transcriptional response to urea regarding capsule production. The transcriptional profile of C. neoformans under urea-supplemented conditions revealed both similar and unique responses to other capsule-inducing conditions, including both intra- and extracellular urea utilization. As one of the most abundant nitrogen sources in the CSF, the ability of Cryptococcus to import urea and induce capsule production may substantially aid this yeast's survival and propagation in the host.

Rising to the challenge of multiple Cryptococcus species and the diseases they cause.

PubMed

Idnurm, Alexander; Lin, Xiaorong

2015-05-01

Cryptococcus neoformans and Cryptococcus gattii are well-studied basidiomyceteous yeasts that are capable of causing disease in healthy and immunocompromised people. The Conference on Cryptococcus and Cryptococcosis (ICCC) is held every three years: the accompanying Special Issue stems from the 9th ICCC and covers a subset of the topics related to these fungi in detail. This conference started with a revised and reduced estimate of disease burden globally, in part due to improved treatment for HIV(+) people. However, mortality from cryptococcosis remains consistently high for those unfortunate to have limited access to therapies or without underlying immunodeficiencies. As such, there are yet still great distances to be covered to address antifungal drug availability, the need for new antifungal agents and the timing and doses of these agents in conjunction with antiviral therapy, underscoring the importance of continued research. A notable point from the 9th ICCC was the research addressing the variation in the pathogen and host populations. Analysis of cryptococcal strain variability, particularly at the molecular level, has resolved distinct lineages with the consequence of a taxonomic revision that divides C. neoformans and C. gattii into seven Cryptococcus species. Similarly, analysis of host factors in so called "immune-competent" individuals revealed previously unrecognized risk factors. Research on these species has established them as important model organisms to understand gene evolution and function in other fungi and eukaryotes. The stage is set for the refinement of research directions, leading ultimately to better treatment of this monophyletic clade of pathogens in the genus Cryptococcus. Copyright © 2015 Elsevier Inc. All rights reserved.

Isolation of Cryptococcus neoformans and other opportunistic fungi from pigeon droppings.

PubMed

Soltani, Maryam; Bayat, Mansour; Hashemi, Seyed J; Zia, Mohammadali; Pestechian, Nader

2013-01-01

Invasive fungal infections cause considerable morbidity and mortality in immunocompromised hosts. Pigeon droppings could especially be a potential carrier in the spread of pathogenic yeasts and mold fungi into the environment. The objective of this study was to isolation of Cryptococcus neoformans and other opportunistic fungi from pigeon droppings. One hundred twenty samples of pigeon droppings were suspended 1:10 in saline solution and then cultured. Identification of C. neoformans was performed on bird seed agar, presence of a capsule on India ink preparation, urease production on urea agar medium and RapID yeast plus system. The identification of candida species was based on micro-morphological analysis on corn meal-Tween 80 agar, RapID yeast plus system and growth in CHROMagar candida. The identification of other fungi was based on macromorphologic, microscopic, biochemical and physiological characteristics. The highest frequency of yeasts and mold fungi were observed in Candida albicans 6.6% and Penicillium spp. 25%. The frequency rate of C. neoformans isolation was 2.5%. Several types of fungi are present in pigeon droppings that can spread in environment and transmit to children and elderly as well as immunocompromised patients who are at increased risk of contracting opportunistic diseases.

Infective capacity of Cryptococcus neoformans and Cryptococcus gattii in a human astrocytoma cell line.

PubMed

Olave, M C; Vargas-Zambrano, J C; Celis, A M; Castañeda, E; González, J M

2017-07-01

Pathogenesis of cryptococcosis in the central nervous system (CNS) is a topic of ongoing research, including the mechanisms by which this fungus invades and infects the brain. Astrocytes, the most common CNS cells, play a fundamental role in the local immune response. Astrocytes might participate in cryptococcosis either as a host or by responding to fungal antigens. To determine the infectivity of Cryptococcus neoformans var. grubii and Cryptococcus gattii in a human astrocytoma cell line and the induction of major histocompatibility complex (MHC) molecules. A glioblastoma cell line was infected with C. neoformans var. grubii and C. gattii blastoconidia labelled with FUN-1 fluorescent stain. The percentage of infection and expression of HLA class I and II molecules were determined by flow cytometry. The interactions between the fungi and cells were observed by fluorescence microscopy. There was no difference between C. neoformans var. grubii and C. gattii in the percentage infection, but C. neoformans var. grubii induced higher expression of HLA class II than C. gattii. More blastoconidia were recovered from C. neoformans-infected cells than from C. gattii infected cells. Cryptococcus neoformans var. grubii may have different virulence mechanisms that allow its survival in human glia-derived cells. © 2017 Blackwell Verlag GmbH.

Innate Immune Responses to Cryptococcus.

PubMed

Heung, Lena J

2017-09-01

Cryptococcus species are encapsulated fungi found in the environment that predominantly cause disease in immunocompromised hosts after inhalation into the lungs. Even with contemporary antifungal regimens, patients with cryptococcosis continue to have high morbidity and mortality rates. The development of more effective therapies may depend on our understanding of the cellular and molecular mechanisms by which the host promotes sterilizing immunity against the fungus. This review will highlight our current knowledge of how Cryptococcus , primarily the species C. neoformans , is sensed by the mammalian host and how subsequent signaling pathways direct the anti-cryptococcal response by effector cells of the innate immune system.

Innate Immune Responses to Cryptococcus

PubMed Central

Heung, Lena J.

2017-01-01

Cryptococcus species are encapsulated fungi found in the environment that predominantly cause disease in immunocompromised hosts after inhalation into the lungs. Even with contemporary antifungal regimens, patients with cryptococcosis continue to have high morbidity and mortality rates. The development of more effective therapies may depend on our understanding of the cellular and molecular mechanisms by which the host promotes sterilizing immunity against the fungus. This review will highlight our current knowledge of how Cryptococcus, primarily the species C. neoformans, is sensed by the mammalian host and how subsequent signaling pathways direct the anti-cryptococcal response by effector cells of the innate immune system. PMID:28936464

Isolation of Cryptococcus neoformans and other opportunistic fungi from pigeon droppings

PubMed Central

Soltani, Maryam; Bayat, Mansour; Hashemi, Seyed J.; Zia, Mohammadali; Pestechian, Nader

2013-01-01

Background: Invasive fungal infections cause considerable morbidity and mortality in immunocompromised hosts. Pigeon droppings could especially be a potential carrier in the spread of pathogenic yeasts and mold fungi into the environment. The objective of this study was to isolation of Cryptococcus neoformans and other opportunistic fungi from pigeon droppings. Materials and Methods: One hundred twenty samples of pigeon droppings were suspended 1:10 in saline solution and then cultured. Identification of C. neoformans was performed on bird seed agar, presence of a capsule on India ink preparation, urease production on urea agar medium and RapID yeast plus system. The identification of candida species was based on micro-morphological analysis on corn meal-Tween 80 agar, RapID yeast plus system and growth in CHROMagar candida. The identification of other fungi was based on macromorphologic, microscopic, biochemical and physiological characteristics. Results: The highest frequency of yeasts and mold fungi were observed in Candida albicans 6.6% and Penicillium spp. 25%. The frequency rate of C. neoformans isolation was 2.5%. Conclusion: Several types of fungi are present in pigeon droppings that can spread in environment and transmit to children and elderly as well as immunocompromised patients who are at increased risk of contracting opportunistic diseases. PMID:23901339

A glycosylphosphatidylinositol anchor is required for membrane localization but dispensable for cell wall association of chitin deacetylase 2 in Cryptococcus neoformans.

PubMed

Gilbert, Nicole M; Baker, Lorina G; Specht, Charles A; Lodge, Jennifer K

2012-01-01

Cell wall proteins (CWPs) mediate important cellular processes in fungi, including adhesion, invasion, biofilm formation, and flocculation. The current model of fungal cell wall organization includes a major class of CWPs covalently bound to β-1,6-glucan via a remnant of a glycosylphosphatidylinositol (GPI) anchor. This model was established by studies of ascomycetes more than a decade ago, and relatively little work has been done with other fungi, although the presumption has been that proteins identified in the cell wall which contain a predicted GPI anchor are covalently linked to cell wall glucans. The pathogenic basidiomycete Cryptococcus neoformans encodes >50 putatively GPI-anchored proteins, some of which have been identified in the cell wall. One of these proteins is chitin deacetylase 2 (Cda2), an enzyme responsible for converting chitin to chitosan, a cell wall polymer recently established as a virulence factor for C. neoformans infection of mammalian hosts. Using a combination of biochemistry, molecular biology, and genetics, we show that Cda2 is GPI anchored to membranes but noncovalently associated with the cell wall by means independent of both its GPI anchor and β-1,6-glucan. We also show that Cda2 produces chitosan when localized to the plasma membrane, but association with the cell wall is not essential for this process, thereby providing insight into the mechanism of chitosan biosynthesis. These results increase our understanding of the surface of C. neoformans and provide models of cell walls likely applicable to other undercharacterized basidiomycete pathogenic fungi. The surface of a pathogenic microbe is a major interface with its host. In fungi, the outer surface consists of a complex matrix known as the cell wall, which includes polysaccharides, proteins, and other molecules. The mammalian host recognizes many of these surface molecules and mounts appropriate responses to combat the microbial infection. Cryptococcus neoformans is a serious fungal pathogen that kills over 600,000 people annually. It converts most of its chitin, a cell wall polysaccharide, to chitosan, which is necessary for virulence. Chitin deacetylase enzymes have been identified in the cell wall, and our studies were undertaken to understand how the deacetylase is linked to the wall and where it has activity. Our results have implications for the current model of chitosan biosynthesis and further challenge the paradigm of covalent linkages between cell wall proteins and polysaccharides through a lipid modification of the protein.

A Glycosylphosphatidylinositol Anchor Is Required for Membrane Localization but Dispensable for Cell Wall Association of Chitin Deacetylase 2 in Cryptococcus neoformans

PubMed Central

Gilbert, Nicole M.; Baker, Lorina G.; Specht, Charles A.; Lodge, Jennifer K.

2012-01-01

ABSTRACT Cell wall proteins (CWPs) mediate important cellular processes in fungi, including adhesion, invasion, biofilm formation, and flocculation. The current model of fungal cell wall organization includes a major class of CWPs covalently bound to β-1,6-glucan via a remnant of a glycosylphosphatidylinositol (GPI) anchor. This model was established by studies of ascomycetes more than a decade ago, and relatively little work has been done with other fungi, although the presumption has been that proteins identified in the cell wall which contain a predicted GPI anchor are covalently linked to cell wall glucans. The pathogenic basidiomycete Cryptococcus neoformans encodes >50 putatively GPI-anchored proteins, some of which have been identified in the cell wall. One of these proteins is chitin deacetylase 2 (Cda2), an enzyme responsible for converting chitin to chitosan, a cell wall polymer recently established as a virulence factor for C. neoformans infection of mammalian hosts. Using a combination of biochemistry, molecular biology, and genetics, we show that Cda2 is GPI anchored to membranes but noncovalently associated with the cell wall by means independent of both its GPI anchor and β-1,6-glucan. We also show that Cda2 produces chitosan when localized to the plasma membrane, but association with the cell wall is not essential for this process, thereby providing insight into the mechanism of chitosan biosynthesis. These results increase our understanding of the surface of C. neoformans and provide models of cell walls likely applicable to other undercharacterized basidiomycete pathogenic fungi. PMID:22354955

Continental Drift and Speciation of the Cryptococcus neoformans and Cryptococcus gattii Species Complexes

PubMed Central

Freij, Joudeh B.; Hann-Soden, Christopher; Taylor, John

2017-01-01

ABSTRACT Genomic analysis has placed the origins of two human-pathogenic fungi, the Cryptococcus gattii species complex and the Cryptococcus neoformans species complex, in South America and Africa, respectively. Molecular clock calculations suggest that the two species separated ~80 to 100 million years ago. This time closely approximates the breakup of the supercontinent Pangea, which gave rise to South America and Africa. On the basis of the geographic distribution of these two species complexes and the coincidence of the evolutionary divergence and Pangea breakup times, we propose that a spatial separation caused by continental drift resulted in the emergence of the C. gattii and C. neoformans species complexes from a Pangean ancestor. We note that, despite the spatial and temporal separation that occurred approximately 100 million years ago, these two species complexes are morphologically similar, share virulence factors, and cause very similar diseases. Continuation of these phenotypic characteristics despite ancient separation suggests the maintenance of similar selection pressures throughout geologic ages. PMID:28435888

Continental Drift and Speciation of the Cryptococcus neoformans and Cryptococcus gattii Species Complexes.

PubMed

Casadevall, Arturo; Freij, Joudeh B; Hann-Soden, Christopher; Taylor, John

2017-01-01

Genomic analysis has placed the origins of two human-pathogenic fungi, the Cryptococcus gattii species complex and the Cryptococcus neoformans species complex, in South America and Africa, respectively. Molecular clock calculations suggest that the two species separated ~80 to 100 million years ago. This time closely approximates the breakup of the supercontinent Pangea, which gave rise to South America and Africa. On the basis of the geographic distribution of these two species complexes and the coincidence of the evolutionary divergence and Pangea breakup times, we propose that a spatial separation caused by continental drift resulted in the emergence of the C. gattii and C. neoformans species complexes from a Pangean ancestor. We note that, despite the spatial and temporal separation that occurred approximately 100 million years ago, these two species complexes are morphologically similar, share virulence factors, and cause very similar diseases. Continuation of these phenotypic characteristics despite ancient separation suggests the maintenance of similar selection pressures throughout geologic ages.

Amoeba provide insight into the origin of virulence in pathogenic fungi.

PubMed

Casadevall, Arturo

2012-01-01

Why are some fungi pathogenic while the majority poses no threat to humans or other hosts? Of the more than 1.5 million fungal species only about 150-300 are pathogenic for humans, and of these, only 10-15 are relatively common pathogens. In contrast, fungi are major pathogens for plants and insects. These facts pose several fundamental questions including the mechanisms responsible for the origin of virulence among the few pathogenic species and the high resistance of mammals to fungal diseases. This essay explores the origin of virulences among environmental fungi with no obvious requirement for animal association and proposes that selection pressures by amoeboid predators led to the emergence of traits that can also promote survival in mammalian hosts. In this regard, analysis of the interactions between the human pathogenic funges Cryptococcus neoformans and amoeba have shown a remarkable similarity with the interaction of this fungus with macrophages. Hence the virulence of environmental pathogenic fungi is proposed to originate from a combination of selection by amoeboid predators and perhaps other soil organism with thermal tolerance sufficient to allow survival in mammalian hosts.

Cryptococcus gattii urease as a virulence factor and the relevance of enzymatic activity in cryptococcosis pathogenesis.

PubMed

Feder, Vanessa; Kmetzsch, Lívia; Staats, Charley Christian; Vidal-Figueiredo, Natalia; Ligabue-Braun, Rodrigo; Carlini, Célia Regina; Vainstein, Marilene Henning

2015-04-01

Ureases (EC 3.5.1.5) are Ni(2+) -dependent metalloenzymes produced by plants, fungi and bacteria that hydrolyze urea to produce ammonia and CO2 . The insertion of nickel atoms into the apo-urease is better characterized in bacteria, and requires at least three accessory proteins: UreD, UreF, and UreG. Our group has demonstrated that ureases possess ureolytic activity-independent biological properties that could contribute to the pathogenicity of urease-producing microorganisms. The presence of urease in pathogenic bacteria strongly correlates with pathogenesis in some human diseases. Some medically important fungi also produce urease, including Cryptococcus neoformans and Cryptococcus gattii. C. gattii is an etiological agent of cryptococcosis, most often affecting immunocompetent individuals. The cryptococcal urease might play an important role in pathogenesis. It has been proposed that ammonia produced via urease action might damage the host endothelium, which would enable yeast transmigration towards the central nervous system. To analyze the role of urease as a virulence factor in C. gattii, we constructed knockout mutants for the structural urease-coding gene URE1 and for genes that code the accessory proteins Ure4 and Ure6. All knockout mutants showed reduced multiplication within macrophages. In intranasally infected mice, the ure1Δ (lacking urease protein) and ure4Δ (enzymatically inactive apo-urease) mutants caused reduced blood burdens and a delayed time of death, whereas the ure6Δ (enzymatically inactive apo-urease) mutant showed time and dose dependency with regard to fungal burden. Our results suggest that C. gattii urease plays an important role in virulence, in part possibly through enzyme activity-independent mechanism(s). © 2015 FEBS.

Evidence that the Human Pathogenic Fungus Cryptococcus neoformans var. grubii May Have Evolved in Africa

PubMed Central

Litvintseva, Anastasia P.; Carbone, Ignazio; Rossouw, Jenny; Thakur, Rameshwari; Govender, Nelesh P.; Mitchell, Thomas G.

2011-01-01

Most of the species of fungi that cause disease in mammals, including Cryptococcus neoformans var. grubii (serotype A), are exogenous and non-contagious. Cryptococcus neoformans var. grubii is associated worldwide with avian and arboreal habitats. This airborne, opportunistic pathogen is profoundly neurotropic and the leading cause of fungal meningitis. Patients with HIV/AIDS have been ravaged by cryptococcosis – an estimated one million new cases occur each year, and mortality approaches 50%. Using phylogenetic and population genetic analyses, we present evidence that C. neoformans var. grubii may have evolved from a diverse population in southern Africa. Our ecological studies support the hypothesis that a few of these strains acquired a new environmental reservoir, the excreta of feral pigeons (Columba livia), and were globally dispersed by the migration of birds and humans. This investigation also discovered a novel arboreal reservoir for highly diverse strains of C. neoformans var. grubii that are restricted to southern Africa, the mopane tree (Colophospermum mopane). This finding may have significant public health implications because these primal strains have optimal potential for evolution and because mopane trees contribute to the local economy as a source of timber, folkloric remedies and the edible mopane worm. PMID:21589919

Combined antifungal therapy against systemic murine infections by rare Cryptococcus species.

PubMed

Thomson, Pamela; Mayayo, Emilio; López-Fernández, Loida; Guarro, Josep; Capilla, Javier

2017-02-01

Cryptococcus albidus and Cryptococcus laurentii are uncommon species of this genus that in recent decades have increasingly caused opportunistic infections in humans, mainly in immunocompromised patients; the best therapy for such infection being unknown. Using a murine model of systemic infection by these fungi, we have evaluated the efficacy of amphotericin B (AMB) at 0.8 mg/kg, administered intravenously, fluconazole (FLC) or voriconazole (VRC), both administered orally, at 25 mg/kg and the combination of AMB plus VRC against three C. albidus and two C. laurentii strains. All the treatments significantly reduced the fungal burden in all the organs studied. The combination showed a synergistic effect in the reduction in fungal load, working better than both monotherapies. The histopathological study confirmed the efficacy of the treatments. © 2016 Blackwell Verlag GmbH.

Polymorphism in Mitochondrial Group I Introns among Cryptococcus neoformans and Cryptococcus gattii Genotypes and Its Association with Drug Susceptibility.

PubMed

Gomes, Felipe E E S; Arantes, Thales D; Fernandes, José A L; Ferreira, Leonardo C; Romero, Héctor; Bosco, Sandra M G; Oliveira, Maria T B; Del Negro, Gilda M B; Theodoro, Raquel C

2018-01-01

Cryptococcosis, one of the most important systemic mycosis in the world, is caused by different genotypes of Cryptococcus neoformans and Cryptococcus gattii , which differ in their ecology, epidemiology, and antifungal susceptibility. Therefore, the search for new molecular markers for genotyping, pathogenicity and drug susceptibility is necessary. Group I introns fulfill the requisites for such task because (i) they are polymorphic sequences; (ii) their self-splicing is inhibited by some drugs; and (iii) their correct splicing under parasitic conditions is indispensable for pathogen survival. Here, we investigated the presence of group I introns in the mitochondrial LSU rRNA gene in 77 Cryptococcus isolates and its possible relation to drug susceptibility. Sequencing revealed two new introns in the LSU rRNA gene. All the introns showed high sequence similarity to other mitochondrial introns from distinct fungi, supporting the hypothesis of an ancient non-allelic invasion. Intron presence was statistically associated with those genotypes reported to be less pathogenic ( p < 0.001). Further virulence assays are needed to confirm this finding. In addition, in vitro antifungal tests indicated that the presence of LSU rRNA introns may influence the minimum inhibitory concentration (MIC) of amphotericin B and 5-fluorocytosine. These findings point to group I introns in the mitochondrial genome of Cryptococcus as potential molecular markers for antifungal resistance, as well as therapeutic targets.

Beech bark disease

Treesearch

David R. Houston

1998-01-01

In forests of North America the beech bark disease (BBD) complex affects American beech, Fagus grandifolia Ehrh. BBD begins when bark tissues, attacked by the exotic beech scale insect, Cryptococcus fagisuga Lind. are rendered susceptible to killing attacks by fungi of the genus Nectria. The principal fungus,...

Profiling a killer, the development of Cryptococcus neoformans

PubMed Central

Kozubowski, Lukasz; Heitman, Joseph

2012-01-01

The ability of fungi to transition between unicellular and multicellular growth has a profound impact on our health and the economy. Many important fungal pathogens of humans, animals, and plants are dimorphic, and the ability to switch between morphological states has been associated with their virulence. Cryptococcus neoformans is a human fungal pathogen that causes life-threatening meningoencephalitis in immunocompromised and, in some cases, immunocompetent hosts. Cryptococcus neoformans grows vegetatively as a budding yeast and switches to hyphal growth during the sexual cycle, which is important in the study of cryptococcal pathogenicity because spores resulting from sexual development are infectious propagules and can colonize the lungs of a host. In addition, sexual reproduction contributes to the genotypic variability of Cryptococcus species, which may lead to increased fitness and virulence. Despite significant advances in our understanding of the mechanisms behind the development of C. neoformans, our knowledge is still incomplete. Recent studies have led to the emergence of many intriguing questions and hypotheses. In this review, we describe and discuss the most interesting aspects of C. neoformans development and address their impact on pathogenicity. PMID:21658085

Genomic epidemiology of Cryptococcus yeasts identifies adaptation to environmental niches underpinning infection across an African HIV/AIDS cohort.

PubMed

Vanhove, Mathieu; Beale, Mathew A; Rhodes, Johanna; Chanda, Duncan; Lakhi, Shabir; Kwenda, Geoffrey; Molloy, Sile; Karunaharan, Natasha; Stone, Neil; Harrison, Thomas S; Bicanic, Tihana; Fisher, Matthew C

2017-04-01

Emerging infections caused by fungi have become a widely recognized global phenomenon and are causing an increasing burden of disease. Genomic techniques are providing new insights into the structure of fungal populations, revealing hitherto undescribed fine-scale adaptations to environments and hosts that govern their emergence as infections. Cryptococcal meningitis is a neglected tropical disease that is responsible for a large proportion of AIDS-related deaths across Africa; however, the ecological determinants that underlie a patient's risk of infection remain largely unexplored. Here, we use genome sequencing and ecological genomics to decipher the evolutionary ecology of the aetiological agents of cryptococcal meningitis, Cryptococcus neoformans and Cryptococcus gattii, across the central African country of Zambia. We show that the occurrence of these two pathogens is differentially associated with biotic (macroecological) and abiotic (physical) factors across two key African ecoregions, Central Miombo woodlands and Zambezi Mopane woodlands. We show that speciation of Cryptococcus has resulted in adaptation to occupy different ecological niches, with C. neoformans found to occupy Zambezi Mopane woodlands and C. gattii primarily recovered from Central Miombo woodlands. Genome sequencing shows that C. neoformans causes 95% of human infections in this region, of which over three-quarters belonged to the globalized lineage VNI. We show that VNI infections are largely associated with urbanized populations in Zambia. Conversely, the majority of C. neoformans isolates recovered in the environment belong to the genetically diverse African-endemic lineage VNB, and we show hitherto unmapped levels of genomic diversity within this lineage. Our results reveal the complex evolutionary ecology that underpins the reservoirs of infection for this, and likely other, deadly pathogenic fungi. © 2016 The Authors. Molecular Ecology Published by John Wiley & Sons Ltd.

Beech Bark Disease

Treesearch

David R. Houston; James T. O' Brien

1983-01-01

Beech bark disease causes significant mortality and defect in American beech, Fagus grandifolia (Ehrh.). The disease results when bark, attacked and altered by the beech scale, Cryptococcus fagisuga Lind., is invaded and killed by fungi, primarily Nectria coccinea var. faginata Lohman, Watson, and Ayers, and sometimes N. galligena Bres.

Proanthocyanidin-rich extracts from cranberry fruit (Vaccinium macrocarpon Ait.) selectively inhibit the growth of human pathogenic fungi Candida spp. and Cryptococcus neoformans.

PubMed

Patel, Kunal D; Scarano, Frank J; Kondo, Miwako; Hurta, Robert A R; Neto, Catherine C

2011-12-28

Cranberry ( Vaccinium macrocarpon ) has been shown in clinical studies to reduce infections caused by Escherichia coli and other bacteria, and proanthocyanidins are believed to play a role. The ability of cranberry to inhibit the growth of opportunistic human fungal pathogens that cause oral, skin, respiratory, and systemic infections has not been well-studied. Fractions from whole cranberry fruit were screened for inhibition of five Candida species and Cryptococcus neoformans , a causative agent of fungal meningitis. Candida glabrata , Candida lusitaniae , Candida krusei , and Cryptococcus neoformans showed significant susceptibility to treatment with cranberry proanthocyanidin fractions in a broth microdilution assay, with minimum inhibitory concentrations as low as 1 μg/mL. MALDI-TOF MS analysis of subfractions detected epicatechin oligomers of up to 12 degrees of polymerization. Those containing larger oligomers caused the strongest inhibition. This study suggests that cranberry has potential as an antifungal agent.

Antimicrobial properties of the stem bark of Saraca indica (Caesalpiniaceae).

PubMed

Sainath, R Shilpakala; Prathiba, J; Malathi, R

2009-01-01

Chloroform, methanol, aqueous and ethanolic extracts of the stem bark of Saraca indica were investigated for their antibacterial and antifungal activity against standard strains of Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Bacillus cereus, Klebsiella pneumoniae, Proteus mirabilis, Salmonella typhimurium and Streptococcus pneumoniae and the fungi: Candida albicans and Cryptococcus albidus. Methanolic and aqueous extract exhibited antimicrobial activity with MIC ranging from 0.5-2% and 1-3% respectively. Methanolic extract exhibited the strongest activity against both bacteria and fungi.

Some aspects of the ecology of Nectria on beech

Treesearch

David Lonsdale; Christine Sherriff

1983-01-01

Observations of the mycoflora of beech bark infested with Cryptococcus fagisuga suggested that Nectria coccinea can colonise sites on and in the outer tissues, and that invasion of imer bark could later develop. Although these sites harboured fungi antagonistic to N. coccinea, experiments suggested that it is...

Thailandins A and B, New Polyene Macrolactone Compounds Isolated from Actinokineospora bangkokensis Strain 44EHW(T), Possessing Antifungal Activity against Anthracnose Fungi and Pathogenic Yeasts.

PubMed

Intra, Bungonsiri; Greule, Anja; Bechthold, Andreas; Euanorasetr, Jirayut; Paululat, Thomas; Panbangred, Watanalai

2016-06-29

Two new polyene macrolactone antibiotics, thailandins A, 1, and B, 2, were isolated from the fermentation broth of rhizosphere soil-associated Actinokineospora bangkokensis strain 44EHW(T). The new compounds from this strain were purified using semipreparative HPLC and Sephadex LH-20 gel filtration while following an antifungal activity guided fractionation. Their structures were elucidated through spectroscopic techniques including UV, HR-ESI-MS, and NMR. These compounds demonstrated broad spectrum antifungal activity against fungi causing anthracnose disease (Colletotrichum gloeosporioides DoA d0762, Colletotrichum gloeosporiodes DoA c1060, and Colletotrichum capsici DoA c1511) as well as pathogenic yeasts (Candida albicans MT 2013/1, Candida parasilopsis DKMU 434, and Cryptococcus neoformans MT 2013/2) with minimum inhibitory concentrations ranging between 16 and 32 μg/mL. This is the first report of polyene antibiotics produced by Actinokineospora species as bioactive compounds against anthracnose fungi and pathogenic yeast strains.

Antimicrobial Potential of Endophytic Fungi Derived from Three Seagrass Species: Cymodocea serrulata, Halophila ovalis and Thalassia hemprichii

PubMed Central

Supaphon, Preuttiporn; Phongpaichit, Souwalak; Rukachaisirikul, Vatcharin; Sakayaroj, Jariya

2013-01-01

Endophytic fungi from three commonly found seagrasses in southern Thailand were explored for their ability to produce antimicrobial metabolites. One hundred and sixty endophytic fungi derived from Cymodocea serrulata (Family Cymodoceaceae), Halophila ovalis and Thalassia hemprichii (Family Hydrocharitaceae) were screened for production of antimicrobial compounds by a colorimetric broth microdilution test against ten human pathogenic microorganisms including Staphylococcus aureus ATCC 25923, a clinical isolate of methicillin-resistant S. aureus, Escherichia coli ATCC 25923, Pseudomonas aeruginosa ATCC 27853, Candida albicans ATCC 90028 and NCPF 3153, Cryptococcus neoformans ATCC 90112 and ATCC 90113 and clinical isolates of Microsporum gypseum and Penicillium marneffei . Sixty-nine percent of the isolates exhibited antimicrobial activity against at least one test strain. Antifungal activity was more pronounced than antibacterial activity. Among the active fungi, seven isolates including Hypocreales sp. PSU-ES26 from C . serrulata , Trichoderma spp. PSU-ES8 and PSU-ES38 from H . ovalis , and Penicillium sp. PSU-ES43, Fusarium sp. PSU-ES73, Stephanonectria sp. PSU-ES172 and an unidentified endophyte PSU-ES190 from T . hemprichii exhibited strong antimicrobial activity against human pathogens with minimum inhibitory concentrations (MIC) of less than 10 µg/ml. The inhibitory extracts at concentrations of 4 times their MIC destroyed the targeted cells as observed by scanning electron microscopy. These results showed the antimicrobial potential of extracts from endophytic fungi from seagrasses. PMID:23977310

Antimicrobial potential of endophytic fungi derived from three seagrass species: Cymodocea serrulata, Halophila ovalis and Thalassia hemprichii.

PubMed

Supaphon, Preuttiporn; Phongpaichit, Souwalak; Rukachaisirikul, Vatcharin; Sakayaroj, Jariya

2013-01-01

Endophytic fungi from three commonly found seagrasses in southern Thailand were explored for their ability to produce antimicrobial metabolites. One hundred and sixty endophytic fungi derived from Cymodoceaserrulata (Family Cymodoceaceae), Halophilaovalis and Thalassiahemprichii (Family Hydrocharitaceae) were screened for production of antimicrobial compounds by a colorimetric broth microdilution test against ten human pathogenic microorganisms including Staphylococcus aureus ATCC 25923, a clinical isolate of methicillin-resistant S. aureus, Escherichia coli ATCC 25923, Pseudomonas aeruginosa ATCC 27853, Candida albicans ATCC 90028 and NCPF 3153, Cryptococcus neoformans ATCC 90112 and ATCC 90113 and clinical isolates of Microsporumgypseum and Penicilliummarneffei. Sixty-nine percent of the isolates exhibited antimicrobial activity against at least one test strain. Antifungal activity was more pronounced than antibacterial activity. Among the active fungi, seven isolates including Hypocreales sp. PSU-ES26 from C. serrulata, Trichoderma spp. PSU-ES8 and PSU-ES38 from H. ovalis, and Penicillium sp. PSU-ES43, Fusarium sp. PSU-ES73, Stephanonectria sp. PSU-ES172 and an unidentified endophyte PSU-ES190 from T. hemprichii exhibited strong antimicrobial activity against human pathogens with minimum inhibitory concentrations (MIC) of less than 10 µg/ml. The inhibitory extracts at concentrations of 4 times their MIC destroyed the targeted cells as observed by scanning electron microscopy. These results showed the antimicrobial potential of extracts from endophytic fungi from seagrasses.

Antifungal Activity of Decyl Gallate against Several Species of Pathogenic Fungi

PubMed Central

de Paula e Silva, Ana Carolina Alves; Costa-Orlandi, Caroline Barcelos; Gullo, Fernanda Patrícia; Sangalli-Leite, Fernanda; de Oliveira, Haroldo Cesar; da Silva, Julhiany de Fátima; Rossi, Suélen Andrea; Benaducci, Tatiane; Wolf, Vanessa Gonçalves; Regasini, Luis Octávio; Petrônio, Maicon Segalla; Silva, Dulce Helena Siqueira; Bolzani, Vanderlan S.; Mendes-Giannini, Maria José Soares

2014-01-01

This work aims to demonstrate that the gallic acid structure modification to the decyl gallate (G14) compound contributed to increase the antifungal activity against several species of pathogenic fungi, mainly, Candida spp., Cryptococcus spp., Paracoccidioides spp., and Histoplasma capsulatum, according to standardized microdilution method described by Clinical Laboratory Standard Institute (CLSI) documents. Moreover this compound has a particularly good selectivity index value, which makes it an excellent candidate for broad-spectrum antifungal prototype and encourages the continuation of subsequent studies for the discovery of its mechanism of action. PMID:25505923

Protection of Melanized Cryptococcus neoformans from Lethal Dose Gamma Irradiation Involves Changes in Melanin's Chemical Structure and Paramagnetism

PubMed Central

Khajo, Abdelahad; Bryan, Ruth A.; Friedman, Matthew; Burger, Richard M.; Levitsky, Yan; Casadevall, Arturo; Magliozzo, Richard S.; Dadachova, Ekaterina

2011-01-01

Certain fungi thrive in highly radioactive environments including the defunct Chernobyl nuclear reactor. Cryptococcus neoformans (C. neoformans), which uses L-3,4-dihydroxyphenylalanine (L-DOPA) to produce melanin, was used here to investigate how gamma radiation under aqueous aerobic conditions affects the properties of melanin, with the aim of gaining insight into its radioprotective role. Exposure of melanized fungal cell in aqueous suspensions to doses of γ-radiation capable of killing 50 to 80% of the cells did not lead to a detectable loss of melanin integrity according to EPR spectra of melanin radicals. Moreover, upon UV-visible (Xe-lamp) illumination of melanized cells, the increase in radical population was unchanged after γ-irradiation. Gamma-irradiation of frozen cell suspensions and storage of samples for several days at 77 K however, produced melanin modification noted by a reduced radical population and reduced photoresponse. More direct evidence for structural modification of melanin came from the detection of soluble products with absorbance maxima near 260 nm in supernatants collected after γ-irradiation of cells and cell-free melanin. These products, which include thiobarbituric acid (TBA)-reactive aldehydes, were also generated by Fenton reagent treatment of cells and cell-free melanin. In an assay of melanin integrity based on the metal (Bi+3) binding capacity of cells, no detectable loss in binding was detected after γ-irradiation. Our results show that melanin in C. neoformans cells is susceptible to some damage by hydroxyl radical formed in lethal radioactive aqueous environments and serves a protective role in melanized fungi that involves sacrificial breakdown. PMID:21966422

Detection of Fungi from an Indoor Environment using Loop-mediated Isothermal Amplification (LAMP) Method.

PubMed

Nakayama, Takako; Yamazaki, Takashi; Yo, Ayaka; Tone, Kazuya; Mahdi Alshahni, Mohamed; Fujisaki, Ryuichi; Makimura, Koichi

2017-01-01

　Loop-mediated isothermal amplification (LAMP) is a useful DNA detection method with high specificity and sensitivity. The LAMP reaction is carried out within a short time at a constant temperature without the need for thermal cycling. We developed a LAMP primer set for detecting a wide range of fungi by aligning the sequences of the large subunit ribosomal RNA gene of Candida albicans (Ascomycota), Cryptococcus neoformans (Basidiomycota), and Mucor racemosus (Mucorales). The threshold of C. albicans rDNA as template with our LAMP primer set was in the range of 10-100 copies per a reaction. In this study, we evaluated the correlation between colony forming units (CFU) and LAMP detection rate using the LAMP method for environmental fungi. The LAMP method should be a useful means of detecting fungi in indoor environments, disaster areas, or even in confined manned spacecraft to prevent allergies or infections caused by fungi.

Spread of beech bark disease in the eastern United States and its relationship to regional forest composition

Treesearch

Randall S. Morin; Andrew M. Liebhold; Patrick C. Tobin; Kurt W. Gottschalk; Eugene Luzader

2007-01-01

Beech bark disease (BBD) is an insect-fungus complex involving the beech scale insect (Cryptococcus fagisuga Lind.) and one of two canker fungi. Beech scale was introduced to Halifax, Nova Scotia around 1890, presumably with the fungus Neonectria coccinea var. faginata Lohm. The disease has subsequently spread...

Paramecium species ingest and kill the cells of the human pathogenic fungus Cryptococcus neoformans.

PubMed

Frager, Shalom Z; Chrisman, Cara J; Shakked, Rachel; Casadevall, Arturo

2010-08-01

A fundamental question in the field of medical mycology is the origin of virulence in those fungal pathogens acquired directly from the environment. In recent years, it was proposed that the virulence of certain environmental animal-pathogenic microbes, such as Cryptococcus neoformans, originated from selection pressures caused by species-specific predation. In this study, we analyzed the interaction of C. neoformans with three Paramecium spp., all of which are ciliated mobile protists. In contrast to the interaction with amoebae, some Paramecium spp. rapidly ingested C. neoformans and killed the fungus. This study establishes yet another type of protist-fungal interaction supporting the notion that animal-pathogenic fungi in the environment are under constant selection by predation.

Sexual Reproduction of Human Fungal Pathogens

PubMed Central

Heitman, Joseph; Carter, Dee A.; Dyer, Paul S.; Soll, David R.

2014-01-01

We review here recent advances in our understanding of sexual reproduction in fungal pathogens that commonly infect humans, including Candida albicans, Cryptococcus neoformans/gattii, and Aspergillus fumigatus. Where appropriate or relevant, we introduce findings on other species associated with human infections. In particular, we focus on rapid advances involving genetic, genomic, and population genetic approaches that have reshaped our view of how fungal pathogens evolve. Rather than being asexual, mitotic, and largely clonal, as was thought to be prevalent as recently as a decade ago, we now appreciate that the vast majority of pathogenic fungi have retained extant sexual, or parasexual, cycles. In some examples, sexual and parasexual unions of pathogenic fungi involve closely related individuals, generating diversity in the population but with more restricted recombination than expected from fertile, sexual, outcrossing and recombining populations. In other cases, species and isolates participate in global outcrossing populations with the capacity for considerable levels of gene flow. These findings illustrate general principles of eukaryotic pathogen emergence with relevance for other fungi, parasitic eukaryotic pathogens, and both unicellular and multicellular eukaryotic organisms. PMID:25085958

[Tropical and travel-related dermatomycoses : Part 2: cutaneous infections due to yeasts, moulds, and dimorphic fungi].

PubMed

Nenoff, P; Reinel, D; Krüger, C; Grob, H; Mugisha, P; Süß, A; Mayser, P

2015-07-01

Besides dermatophytoses, a broad range of cutaneous infections due to yeasts and moulds may occur in subtropical and tropical countries where they can affect travellers. Not to be forgotten are endemic occurring dimorphic or biphasic fungi in countries with hot climate, which cause systemic and secondary cutaneous infections in immunosuppressed and immunocompetent people. In the tropics, the prevalence of pityriasis versicolor, caused by the lipophilic yeast Malassezia spp., is about 30-40 %, in distinct areas even 50 %. Increased hyperhidrosis under tropical conditions and simultaneously humidity congestion have to be considered as significant disposing factors for pityriasis versicolor. In tropical countries, therefore, an exacerbation of a preexisting pityriasis versicolor in travellers is not rare. Today, mostly genital yeast infections due to the new species Candida africana can be found worldwide. Due to migration from Africa this yeast pathogen has reached Germany and Europe. Eumycetomas due to mould fungi are rarely diagnosed in Europe. These deep cutaneous mould infections are only found in immigrants from African countries. The therapy of eumycetoma is protracted and often not successful. Cutaneous cryptococcoses due to the yeast species Cryptococcus neoformans and Cryptococcus gattii occur worldwide; however, they are found more frequently in the tropics. Immunosuppressed patients, especially those with HIV/AIDS, are affected by cryptococcoses. Furthermore, Cryptococcus gattii also causes infections in immunocompetent hosts in Central Africa, Australia, California, and Central America.Rarely found are infections due to dimorphic fungi after travel to countries where these fungal pathogens are endemic. In individual cases, cutaneous or lymphogenic transferred sporotrichosis due to Sporothrix schenkii can occur. Furthermore, scarcely known is secondary cutaneous coccidioidomycosis due to Coccidioides immitis after travelling to desert-like endemic regions in southwestern states of the United States and in Latin America, where primary respiratory infection due to this biphasic fungus can be acquired. The antifungal agent itraconazole is the treatment of choice for sporotrichosis and coccidioidomycosis. Talaromyces marneffei-until recently known as Penicillium marneffei-is only found in Southeastern Asia. Mycosis due to this dimorphic fungus has to be considered as an AIDS-defining opportunistic infection. After hematogeneous spread, Talaromyces marneffei affects the skin and mucous membranes of the mouth. Amphotericin B and itraconazole can be used for therapy.

Ras-Mediated Signal Transduction and Virulence in Human Pathogenic Fungi

PubMed Central

Fortwendel, Jarrod R.

2013-01-01

Signal transduction pathways regulating growth and stress responses are areas of significant study in the effort to delineate pathogenic mechanisms of fungi. In-depth knowledge of signal transduction events deepens our understanding of how a fungal pathogen is able to sense changes in the environment and respond accordingly by modulation of gene expression and re-organization of cellular activities to optimize fitness. Members of the Ras protein family are important regulators of growth and differentiation in eukaryotic organisms, and have been the focus of numerous studies exploring fungal pathogenesis. Here, the current data regarding Ras signal transduction are reviewed for three major pathogenic fungi: Cryptococcus neoformans, Candida albicans and Aspergillus fumigatus. Particular emphasis is placed on Ras-protein interactions during control of morphogenesis, stress response and virulence. PMID:24855584

3-Bromopyruvate: a novel antifungal agent against the human pathogen Cryptococcus neoformans.

PubMed

Dyląg, Mariusz; Lis, Paweł; Niedźwiecka, Katarzyna; Ko, Young H; Pedersen, Peter L; Goffeau, Andre; Ułaszewski, Stanisław

2013-05-03

We have investigated the antifungal activity of the pyruvic acid analogue: 3-bromopyruvate (3-BP). Growth inhibition by 3-BP of 110 strains of yeast-like and filamentous fungi was tested by standard spot tests or microdilution method. The human pathogen Cryptococcus neoformans exhibited a low Minimal Inhibitory Concentration (MIC) of 0.12-0.15 mM 3-BP. The high toxicity of 3-BP toward C. neoformans correlated with high intracellular accumulation of 3-BP and also with low levels of intracellular ATP and glutathione. Weak cytotoxicity towards mammalian cells and lack of resistance conferred by the PDR (Pleiotropic Drug Resistance) network in the yeast Saccharomyces cerevisiae, are other properties of 3-BP that makes it a novel promising anticryptococcal drug. Copyright © 2013 Elsevier Inc. All rights reserved.

Characterization of additional components of the environmental pH-sensing complex in the pathogenic fungus Cryptococcus neoformans.

PubMed

Pianalto, Kaila M; Ost, Kyla S; Brown, Hannah E; Alspaugh, J Andrew

2018-05-16

Pathogenic microorganisms must adapt to changes in their immediate surroundings, including alterations in pH, to survive the shift from the external environment to that of the infected host. In the basidiomycete fungal pathogen Cryptococcus neoformans , these pH changes are primarily sensed by the fungal-specific, alkaline pH-sensing Rim/Pal pathway. The C. neoformans Rim pathway has diverged significantly from that described in ascomycete fungi. We recently identified the C. neoformans putative pH sensor Rra1, which activates the Rim pathway in response to elevated pH. In this study, we probed the function of Rra1 by analyzing its cellular localization and performing protein co-immunoprecipitation to identify potential Rra1 interactors. We found that Rra1 does not strongly colocalize or interact with immediate downstream Rim pathway components. However, these experiments identified a novel Rra1 interactor, the previously uncharacterized C. neoformans nucleosome assembly protein 1 (Nap1), which was required for Rim pathway activation. We observed that Nap1 specifically binds to the C-terminal tail of the Rra1 sensor, likely promoting Rra1 protein stability. This function of Nap1 is conserved in fungi closely related to C. neoformans that contain Rra1 orthologs, but not in the more distantly-related ascomycete fungus Saccharomyces cerevisiae In conclusion, our findings have revealed the sophisticated, yet distinct, molecular mechanisms by which closely and distantly related microbial phyla rapidly adapt to environmental signals and changes such as alterations in pH. Published under license by The American Society for Biochemistry and Molecular Biology, Inc.

Isolation of 2-deoxy-scyllo-inosose (DOI)-assimilating yeasts and cloning and characterization of the DOI reductase gene of Cryptococcus podzolicus ND1.

PubMed

Ara, Satoshi; Yamazaki, Harutake; Takaku, Hiroaki

2018-04-01

2-Deoxy-scyllo-inosose (DOI) is the first intermediate in the 2-deoxystreptamine-containing aminoglycoside antibiotic biosynthesis pathway and has a six-membered carbocycle structure. DOI is a valuable material because it is easily converted to aromatic compounds and carbasugar derivatives. In this study, we isolated yeast strains capable of assimilating DOI as a carbon source. One of the strains, Cryptococcus podzolicus ND1, mainly converted DOI to scyllo-quercitol and (-)-vibo-quercitol, which is a valuable compound used as an antihypoglycemia agent and as a heat storage material. An NADH-dependent DOI reductase coding gene, DOIR, from C. podzolicus ND1 was cloned and successfully overexpressed in Escherichia coli. The purified protein catalyzed the irreversible reduction of DOI with NADH and converted DOI into (-)-vibo-quercitol. The enzyme had an optimal pH of 8.5 and optimal temperature of 35°C, respectively. The k cat of this enzyme was 9.98 s -1 , and the K m values for DOI and NADH were 4.38 and 0.24 mM, respectively. The enzyme showed a strong preference for NADH and showed no activity with NADPH. Multiple-alignment analysis of DOI reductase revealed that it belongs to the GFO_IDH_MocA protein family and is an inositol dehydrogenase homolog in other fungi, such as Cryptococcus gattii, and bacteria, such as Bacillus subtilis. This is the first identification of a DOI-assimilating yeast and a gene involved in DOI metabolism in fungi. Copyright © 2017 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Extracellular vesicle-mediated export of fungal RNA

PubMed Central

Peres da Silva, Roberta; Puccia, Rosana; Rodrigues, Marcio L.; Oliveira, Débora L.; Joffe, Luna S.; César, Gabriele V.; Nimrichter, Leonardo; Goldenberg, Samuel; Alves, Lysangela R.

2015-01-01

Extracellular vesicles (EVs) play an important role in the biology of various organisms, including fungi, in which they are required for the trafficking of molecules across the cell wall. Fungal EVs contain a complex combination of macromolecules, including proteins, lipids and glycans. In this work, we aimed to describe and characterize RNA in EV preparations from the human pathogens Cryptococcus neoformans, Paracoccidiodes brasiliensis and Candida albicans, and from the model yeast Saccharomyces cerevisiae. The EV RNA content consisted mostly of molecules less than 250 nt long and the reads obtained aligned with intergenic and intronic regions or specific positions within the mRNA. We identified 114 ncRNAs, among them, six small nucleolar (snoRNA), two small nuclear (snRNA), two ribosomal (rRNA) and one transfer (tRNA) common to all the species considered, together with 20 sequences with features consistent with miRNAs. We also observed some copurified mRNAs, as suggested by reads covering entire transcripts, including those involved in vesicle-mediated transport and metabolic pathways. We characterized for the first time RNA molecules present in EVs produced by fungi. Our results suggest that RNA-containing vesicles may be determinant for various biological processes, including cell communication and pathogenesis. PMID:25586039

Structure of a fungal form of aspartate semialdehyde dehydrogenase from Cryptococcus neoformans

PubMed Central

Dahal, Gopal; Viola, Ronald E.

2015-01-01

Aspartate semialdehyde dehydrogenase (ASADH) functions at a critical junction in the aspartate-biosynthetic pathway and represents a valid target for antimicrobial drug design. This enzyme catalyzes the NADPH-dependent reductive dephosphorylation of β-aspartyl phosphate to produce the key intermediate aspartate semialdehyde. Production of this intermediate represents the first committed step in the biosynthesis of the essential amino acids methionine, isoleucine and threonine in fungi, and also the amino acid lysine in bacteria. The structure of a new fungal form of ASADH from Cryptococcus neoformans has been determined to 2.6 Å resolution. The overall structure of CnASADH is similar to those of its bacterial orthologs, but with some critical differences both in biological assembly and in secondary-structural features that can potentially be exploited for the development of species-selective drugs. PMID:26527262

Antifungal activity of synthetic naphthoquinones against dermatophytes and opportunistic fungi: preliminary mechanism-of-action tests.

PubMed

Ferreira, Maria do Perpetuo Socorro Borges Carriço; Cardoso, Mariana Filomena do Carmo; da Silva, Fernando de Carvalho; Ferreira, Vitor Francisco; Lima, Emerson Silva; Souza, João Vicente Braga

2014-07-06

This study evaluated the antifungal activities of synthetic naphthoquinones against opportunistic and dermatophytic fungi and their preliminary mechanisms of action. The minimum inhibitory concentrations (MICs) of four synthetic naphthoquinones for 89 microorganisms, including opportunistic yeast agents, dermatophytes and opportunistic filamentous fungi, were determined. The compound that exhibited the best activity was assessed for its action against the cell wall (sorbitol test), for interference associated with ergosterol interaction, for osmotic balance (K+ efflux) and for membrane leakage of substances that absorb at the wavelength of 260 nm. All tested naphthoquinones exhibited antifungal activity, and compound IVS320 (3a,10b-dihydro-1H-cyclopenta [b] naphtho [2,3-d] furan-5,10-dione)-dione) demonstrated the lowest MICs across the tested species. The MIC of IVS320 was particularly low for dermatophytes (values ranging from 5-28 μg/mL) and Cryptococcus spp. (3-5 μg/mL). In preliminary mechanism-of-action tests, IVS320 did not alter the fungal cell wall but did cause problems in terms of cell membrane permeability (efflux of K+ and leakage of substances that absorb at 260 nm). This last effect was unrelated to ergosterol interactions with the membrane.

Linking Antimicrobial Potential of Natural Products Derived from Aquatic Organisms and Microbes Involved in Alzheimer's Disease - A Review.

PubMed

Stojkovic, Dejan; Kostic, Marina; Smiljkovic, Marija; Aleksic, Milena; Vasiljevic, Perica; Nikolic, Milos; Sokovic, Marina

2018-03-08

The following review is oriented towards microbes linked to Alzheimer's disease (AD) and antimicrobial effect of compounds and extracts derived from aquatic organisms against specific bacteria, fungi and viruses which were found previously in patients suffering from AD. Major group of microbes linked to AD include bacteria: Chlamydia pneumoniae, Helicobacter pylori, Porphyromonas gingivalis, Fusobacterium nucleatum, Prevotella intermedia, Actinomyces naeslundii, spirochete group; fungi: Candida sp., Cryptococcus sp., Saccharomyces sp., Malassezia sp., Botrytis sp., and viruses: herpes simplex virus type 1 (HSV-1), Human cytomegalovirus (CMV), hepatitis C virus (HCV). In the light of that fact, this review is the first to link antimicrobial potential of aquatic organisms against these sorts of microbes. This literature review might serve as a starting platform to develop novel supportive therapy for patients suffering from AD and to possibly prevent escalation of the disease in patients already having high risk factors for AD occurrence. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

One-step synthesis of carbohydrate esters as antibacterial and antifungal agents.

PubMed

AlFindee, Madher N; Zhang, Qian; Subedi, Yagya Prasad; Shrestha, Jaya P; Kawasaki, Yukie; Grilley, Michelle; Takemoto, Jon Y; Chang, Cheng-Wei Tom

2018-02-01

Carbohydrate esters are biodegradable, and the degraded adducts are naturally occurring carbohydrates and fatty acids which are environmentally friendly and non-toxic to human. A simple one-step regioselective acylation of mono-carbohydrates has been developed that leads to the synthesis of a wide range of carbohydrate esters. Screening of these acylated carbohydrates revealed that several compounds were active against a panel of bacteria and fungi, including Staphylococcus aureus, methicillin-resistant S. aureus (MRSA), Candida albicans, Cryptococcus neoformans, Aspergillus flavus and Fusarium graminearum. Unlike prior studies on carbohydrate esters that focus only on antibacterial applications, our compounds are found to be active against both bacteria and fungi. Furthermore, the synthetic methodology is suitable to scale-up production for a variety of acylated carbohydrates. The identified lead compound, MAN014, can be used as an antimicrobial in applications such as food processing and preservation and for treatment of bacterial and fungal diseases in animals and plants. Copyright © 2017 Elsevier Ltd. All rights reserved.

Causative agents of nosocomial mycoses.

PubMed

Tomsiková, A

2002-01-01

In the last few years mycoses have been caused by fungi formerly considered to be harmless for humans. They cause diseases of plants and insects; some of them are also used in the industry. They are now usually called "emerging fungi". We investigated this flora with respect to their potential to cause infections in hospitals. These fungi are present in the air, on medical objects and instrumentation, in the respiratory tract and on the hands of hospital staff; other sources have been identified in the use of iatrogenic methods. Mycotic diseases, their risk factors, their clinical pictures, and spectra of agents were analyzed in 1990-2000; the results were compared with data in the literature. Transplantations were the most frequent risk factors, fungemia and abscess the most frequent clinical picture and filamentous fungi (genera Absidia, Acremonium, Alternaria, Apophysomyces, Aspergillus, Bipolaris, Cladophialophora, Cunninghamella, Exserohilum, Fusarium, Chaetomium, Chrysosporium, Lecythophora, Ochroconis, Paecilomyces, Pythium, Rhizopus, Scedosporium, Scopulariopsis) were the most frequent agents of nosocomial infections. These filamentous fungi and also some yeasts (genera Candida, Cryptococcus, Trichosporon) bring about different clinical syndromes in both immunocompromised and immunocompetent patients.

Silver nanoparticle production by the fungus Fusarium oxysporum: nanoparticle characterisation and analysis of antifungal activity against pathogenic yeasts

PubMed Central

Ishida, Kelly; Cipriano, Talita Ferreira; Rocha, Gustavo Miranda; Weissmüller, Gilberto; Gomes, Fabio; Miranda, Kildare; Rozental, Sonia

2013-01-01

The microbial synthesis of nanoparticles is a green chemistry approach that combines nanotechnology and microbial biotechnology. The aim of this study was to obtain silver nanoparticles (SNPs) using aqueous extract from the filamentous fungus Fusarium oxysporum as an alternative to chemical procedures and to evaluate its antifungal activity. SNPs production increased in a concentration-dependent way up to 1 mM silver nitrate until 30 days of reaction. Monodispersed and spherical SNPs were predominantly produced. After 60 days, it was possible to observe degenerated SNPs with in additional needle morphology. The SNPs showed a high antifungal activity against Candida and Cryptococcus , with minimum inhibitory concentration values ≤ 1.68 µg/mL for both genera. Morphological alterations of Cryptococcus neoformans treated with SNPs were observed such as disruption of the cell wall and cytoplasmic membrane and lost of the cytoplasm content. This work revealed that SNPs can be easily produced by F. oxysporum aqueous extracts and may be a feasible, low-cost, environmentally friendly method for generating stable and uniformly sized SNPs. Finally, we have demonstrated that these SNPs are active against pathogenic fungi, such as Candida and Cryptococcus . PMID:24714966

Silver nanoparticle production by the fungus Fusarium oxysporum: nanoparticle characterisation and analysis of antifungal activity against pathogenic yeasts.

PubMed

Ishida, Kelly; Cipriano, Talita Ferreira; Rocha, Gustavo Miranda; Weissmüller, Gilberto; Gomes, Fabio; Miranda, Kildare; Rozental, Sonia

2014-04-01

The microbial synthesis of nanoparticles is a green chemistry approach that combines nanotechnology and microbial biotechnology. The aim of this study was to obtain silver nanoparticles (SNPs) using aqueous extract from the filamentous fungus Fusarium oxysporum as an alternative to chemical procedures and to evaluate its antifungal activity. SNPs production increased in a concentration-dependent way up to 1 mM silver nitrate until 30 days of reaction. Monodispersed and spherical SNPs were predominantly produced. After 60 days, it was possible to observe degenerated SNPs with in additional needle morphology. The SNPs showed a high antifungal activity against Candida and Cryptococcus , with minimum inhibitory concentration values ≤ 1.68 µg/mL for both genera. Morphological alterations of Cryptococcus neoformans treated with SNPs were observed such as disruption of the cell wall and cytoplasmic membrane and lost of the cytoplasm content. This work revealed that SNPs can be easily produced by F. oxysporum aqueous extracts and may be a feasible, low-cost, environmentally friendly method for generating stable and uniformly sized SNPs. Finally, we have demonstrated that these SNPs are active against pathogenic fungi, such as Candida and Cryptococcus.

Fungi that Infect Humans.

PubMed

Köhler, Julia R; Hube, Bernhard; Puccia, Rosana; Casadevall, Arturo; Perfect, John R

2017-06-01

Fungi must meet four criteria to infect humans: growth at human body temperatures, circumvention or penetration of surface barriers, lysis and absorption of tissue, and resistance to immune defenses, including elevated body temperatures. Morphogenesis between small round, detachable cells and long, connected cells is the mechanism by which fungi solve problems of locomotion around or through host barriers. Secretion of lytic enzymes, and uptake systems for the released nutrients, are necessary if a fungus is to nutritionally utilize human tissue. Last, the potent human immune system evolved in the interaction with potential fungal pathogens, so few fungi meet all four conditions for a healthy human host. Paradoxically, the advances of modern medicine have made millions of people newly susceptible to fungal infections by disrupting immune defenses. This article explores how different members of four fungal phyla use different strategies to fulfill the four criteria to infect humans: the Entomophthorales, the Mucorales, the Ascomycota, and the Basidiomycota. Unique traits confer human pathogenic potential on various important members of these phyla: pathogenic Onygenales comprising thermal dimorphs such as Histoplasma and Coccidioides ; the Cryptococcus spp. that infect immunocompromised as well as healthy humans; and important pathogens of immunocompromised patients- Candida , Pneumocystis , and Aspergillus spp. Also discussed are agents of neglected tropical diseases important in global health such as mycetoma and paracoccidiomycosis and common pathogens rarely implicated in serious illness such as dermatophytes. Commensalism is considered, as well as parasitism, in shaping genomes and physiological systems of hosts and fungi during evolution.

The diversity and distribution of fungi on residential surfaces.

PubMed

Adams, Rachel I; Miletto, Marzia; Taylor, John W; Bruns, Thomas D

2013-01-01

The predominant hypothesis regarding the composition of microbial assemblages in indoor environments is that fungal assemblages are structured by outdoor air with a moderate contribution by surface growth, whereas indoor bacterial assemblages represent a mixture of bacteria entered from outdoor air, shed by building inhabitants, and grown on surfaces. To test the fungal aspect of this hypothesis, we sampled fungi from three surface types likely to support growth and therefore possible contributors of fungi to indoor air: drains in kitchens and bathrooms, sills beneath condensation-prone windows, and skin of human inhabitants. Sampling was done in replicated units of a university-housing complex without reported mold problems, and sequences were analyzed using both QIIME and the new UPARSE approach to OTU-binning, to the same result. Surfaces demonstrated a mycological profile similar to that of outdoor air from the same locality, and assemblages clustered by surface type. "Weedy" genera typical of indoor air, such as Cladosporium and Cryptococcus, were abundant on sills, as were a diverse set of fungi of likely outdoor origin. Drains supported more depauperate assemblages than the other surfaces and contained thermotolerant genera such as Exophiala, Candida, and Fusarium. Most surprising was the composition detected on residents' foreheads. In addition to harboring Malassezia, a known human commensal, skin also possessed a surprising richness of non-resident fungi, including plant pathogens such as ergot (Claviceps purperea). Overall, fungal richness across indoor surfaces was high, but based on known autecologies, most of these fungi were unlikely to be growing on surfaces. We conclude that while some endogenous fungal growth on typical household surfaces does occur, particularly on drains and skin, all residential surfaces appear - to varying degrees - to be passive collectors of airborne fungi of putative outdoor origin, a view of the origins of the indoor microbiome quite different from bacteria.

In Vitro Activities of Terbinafine against Cutaneous Isolates of Candida albicans and Other Pathogenic Yeasts

PubMed Central

Ryder, Neil S.; Wagner, Sonja; Leitner, Ingrid

1998-01-01

Terbinafine is active in vitro against a wide range of pathogenic fungi, including dermatophytes, molds, dimorphic fungi, and some yeasts, but earlier studies indicated that the drug had little activity against Candida albicans. In contrast, clinical studies have shown topical and oral terbinafine to be active in cutaneous candidiasis and Candida nail infections. In order to define the anti-Candida activity of terbinafine, we tested the drug against 350 fresh clinical isolates and additional strains by using a broth dilution assay standardized according to the guidelines of the National Committee for Clinical Laboratory Standards (NCCLS) M27-A assay. Terbinafine was found to have an MIC of 1 μg/ml for reference C. albicans strains. For 259 clinical isolates, the MIC at which 50% of the isolates are inhibited (MIC50) of terbinafine was 1 μg/ml (fluconazole, 0.5 μg/ml), and the MIC90 was 4 μg/ml (fluconazole, 1 μg/ml). Terbinafine was highly active against Candida parapsilosis (MIC90, 0.125 μg/ml) and showed potentially interesting activity against isolates of Candida dubliniensis, Candida guilliermondii, Candida humicola, and Candida lusitaniae. It was not active against the Candida glabrata, Candida krusei, and Candida tropicalis isolates in this assay. Cryptococcus laurentii and Cryptococcus neoformans were highly susceptible to terbinafine, with MICs of 0.06 to 0.25 μg/ml. The NCCLS macrodilution assay provides reproducible in vitro data for terbinafine against Candida and other yeasts. The MICs for C. albicans and C. parapsilosis are compatible with the known clinical efficacy of terbinafine in cutaneous infections, while the clinical relevance of its activities against the other species has yet to be determined. PMID:9593126

Tracking the emerging human pathogen Pseudallescheria boydii by using highly specific monoclonal antibodies.

PubMed

Thornton, Christopher R

2009-05-01

Pseudallescheria boydii has long been known to cause white grain mycetoma in immunocompetent humans, but it has recently emerged as an opportunistic pathogen of humans, causing potentially fatal invasive infections in immunocompromised individuals and evacuees of natural disasters, such as tsunamis and hurricanes. The diagnosis of P. boydii is problematic since it exhibits morphological characteristics similar to those of other hyaline fungi that cause infectious diseases, such as Aspergillus fumigatus and Scedosporium prolificans. This paper describes the development of immunoglobulin M (IgM) and IgG1 kappa-light chain monoclonal antibodies (MAbs) specific to P. boydii and certain closely related fungi. The MAbs bind to an immunodominant carbohydrate epitope on an extracellular 120-kDa antigen present in the spore and hyphal cell walls of P. boydii and Scedosporium apiospermum. The MAbs do not react with S. prolificans, Scedosporium dehoogii, or a large number of clinically relevant fungi, including A. fumigatus, Candida albicans, Cryptococcus neoformans, Fusarium solani, and Rhizopus oryzae. The MAbs were used in immunofluorescence and double-antibody sandwich enzyme-linked immunosorbent assays (DAS-ELISAs) to accurately differentiate P. boydii from other infectious fungi and to track the pathogen in environmental samples. Specificity of the DAS-ELISA was confirmed by sequencing of the internally transcribed spacer 1 (ITS1)-5.8S-ITS2 rRNA-encoding regions of environmental isolates.

Cell wall proteome of pathogenic fungi.

PubMed

Karkowska-Kuleta, Justyna; Kozik, Andrzej

2015-01-01

A fast development of a wide variety of proteomic techniques supported by mass spectrometry coupled with high performance liquid chromatography has been observed in recent years. It significantly contributes to the progress in research on the cell wall, very important part of the cells of pathogenic fungi. This complicated structure composed of different polysaccharides, proteins, lipids and melanin, plays a key role in interactions with the host during infection. Changes in the set of the surface-exposed proteins under different environmental conditions provide an effective way for pathogens to respond, adapt and survive in the new niches of infection. This work summarizes the current state of knowledge on proteins, studied both qualitatively and quantitatively, and found within the cell wall of fungal pathogens for humans, including Candida albicans, Candida glabrata, Aspergillus fumigatus, Cryptococcus neoformans and other medically important fungi. The described proteomic studies involved the isolation and fractionation of particular sets of proteins of interest with various techniques, often based on differences in their linkages to the polysaccharide scaffold. Furthermore, the proteinaceous contents of extracellular vesicles ("virulence bags") of C. albicans, C. neoformans, Histoplasma capsulatum and Paracoccidioides brasiliensis are compared, because their production can partially explain the problem of non-classical protein secretion by fungi. The role assigned to surface-exposed proteins in pathogenesis of fungal infections is enormously high, thus justifying the need for further investigation of cell wall proteomes.

Role of pathogen-associated molecular patterns (PAMPS) in immune responses to fungal infections.

PubMed

Taghavi, Mehdi; Khosravi, Alireza; Mortaz, Esmaeil; Nikaein, Donya; Athari, Seyyed Shamsadin

2017-08-05

Recent years have seen the rise of invasive fungal infections, which are mostly due to the increase in patients. Three major opportunistic fungal species in human are Aspergillus fumigatus, Candida albicans, and Cryptococcus neoformans that pose the biggest concern for these immunocompromised patients' mortality. The growing occurrence of opportunistic fungal infections has sparked the interest to understand defense mechanisms against pathogenic fungi. Toll-like receptors (TLRs), as a part of innate immune system, play an important role for recognizing the invading microorganisms and initiating sufficient immune responses. Recent studies have revealed an integrated role for TLR, signaling inactivating immune defense mechanisms against exact fungi. Among TLRs, TLR2 and TLR4 are the major participants in fungi recognition. The present paper highlights the role of TLR participants in fungal recognition as well as their mechanisms. Copyright © 2016 Elsevier B.V. All rights reserved.

Fungi from interior organs of free-living small mammals in Czechoslovakia and Yugoslavia.

PubMed

Hubálek, Z; Rosický, B; Otcenásek, M

1980-01-01

A total of 308 fungi was isolated from interior organs (lungs, spleen, liver) of 529 small mammals belonging to 21 species, 7 families and 3 orders (Insectivora, Chiroptera, Rodentia), some of these being potentially pathogenic to vertebrates (e.g. Aspergillus flavus, A. fumigatus, Geotrichum candidum, Mucor pusillus, Rhizopus arrhizus). In one vole (Microtus arvalis) captured in South Moravia, adiaspiromycosis (Emmonsia crescens) was demonstrated. Comparison of mycoflora of hair and that of interior organs of wild small mammals revealed that out of the total number of isolates the following fungi were represented in a higher proportion from visceral organs than from the hair: Aspergillus (A. amstelodami, A. flavus, A. repens), Aureobasidium (A. pullulans), Candida, Cladosporium (C. herbarum), Cryptococcus, Fusarium, Gliocladium (G. deliquescens), Helminthosporium, Kloeckera, Mucor (M. fragilis, M. hiemalis, M. pusillus), Paecilomyces marquandii, Penicillium (P. purpurogenum), Phoma, Rhizopus arrhizus, Scopulariopsis (S. candida, S. koningii) and Torulopsis.

Esculin-based medium for isolation and identification of Cryptococcus neoformans.

PubMed Central

Edberg, S C; Chaskes, S J; Alture-Werber, E; Singer, J M

1980-01-01

A simple medium was developed, using esculin as the substrate, for the isolation and identification of Cryptococcus neoformans. C. neoformans produced a brown-black pigment on the medium; all other yeasts produced no pigment or were light yellow. Esculin is beta-glucose-6,7-dihydroxycoumarin. C. neoformans produced pigment because the 6,7-dihydroxycoumarin component of the esculin molecule was converted to a melanin-like pigment. We think the reaction was similar to the conversion of diphenols, aminophenols, and diaminobenzenes to melanin. Laboratory studies with isolates of C. neoformans, C. albidus, C. luteolus, and C. terreus and representatives of the genera Candida, Torulopsis, Geotrichum, and Rhodotorula, plus environmental field studies, demonstrated that over 95% of C. neoformans isolates were correctly identified, whereas all other fungi were excluded. Esculin agar was a sensitive, specific medium for the isolation and identification of C. neoformans. It was inexpensive and had a long storage life. Images PMID:7012169

[Groups and sources of yeasts in house dust].

PubMed

Glushakova, A M; Zheltikova, T M; Chernov, I Iu

2004-01-01

House dust contains bacteria, mycelial fungi, microarthropods, and yeasts. The house dust samples collected in 25 apartments in Moscow and the Moscow region were found to contain yeasts belonging to the genera Candida, Cryptococcus, Debaryomyces, Rhodotorula, Sporobolomyces, and Trichosporon. The most frequently encountered microorganisms were typical epiphytic yeasts, such as Cryptococcus diffluens and Rhodotorula mucilaginosa, which are capable of long-term preservation in an inactive state. The direct source of epiphytic yeasts occurring in the house dust might be the indoor plants, which were contaminated with these yeasts, albeit to a lesser degree than outdoor plants. Along with the typical epiphytic yeasts, the house dust contained the opportunistic yeast pathogens Candida catenulata, C. guillermondii, C. haemulonii, C. rugosa, and C. tropicalis, which are known as the causal agents of candidiasis. We failed to reveal any correlation between the abundance of particular yeast species in the house dust, residential characteristics, and the atopic dermatitis of the inhabitants.

[Effect of Invasive Herb Species on the Structure of Soil Yeast Complexes in Mixed Forests Exemplified by Impatiens parviflora DC].

PubMed

Glushakova, A M; Kachalkin, A V; Chernov, I Yu

2015-01-01

Yeast abundance and diversity in a mixed forest sod-podzol soil under Impatiens parviflora DC plants was studied in comparison with unimpaired aboriginal herbaceous plants typical of the Mid-Russian secondary, after-forest meadow. The study was carried out throughout the vegetation period. Standard microbiological plating techniques revealed 36 yeast species. Typical pedobiotic (Cryptococcus podzolicus, Wickerhamomyces anomalus) and eurybiotic yeast species (Rhodotorula mucilaginosa) predominated in both biotopes. The relative abundance of the autochthonous soil yeast species Cryptococcus podzolicus was higher in the soil under aboriginal herbs than under Impatiens parviflora. Sites with aboriginal vegetation were also characterized by high abundance of the pedogamous species Schwanniomyces castelli and Torulaspora delbrueckii. The share of yeastlike Trichosporon fungi with high hydrolytic activity was considerably higher under adventitious plants Impatiens parviflora, as well as in the previously studied soil under Heracleum sosnowskyi.

SEM study of the effects of bacteria and yeasts on wood decay by brown and white-rot fungi. [Enterobacter, Cryptococcus Pichia, and Saccharomyces

DOE Office of Scientific and Technical Information (OSTI.GOV)

Blanchette, R.A.; Shaw, C.G.; Cohen, A.L.

The scanning electron microscope was used to 1) examine the associations among microorganisms during wood decay and 2) observe the effect of these organisms on degradation of cell wall components. Bacteria (Enterobacter) and yeasts (Cryptococcus Pichia, and Saccharomyces) were found to have a mutualistic association with a white-rot fungus during decay of coniferous wood. Coriolus (Polyporus versicolar) degraded cell wall components in a typical ''erosion trough'' manner (i.e., by lysing zones around fungal hyphae). Bacteria and yeasts were seen only in these lysed zones. Typical gross decay patterns caused by the white-rot fungus were unaltered by bacteria and yeasts. Themore » SEM study suggests that the decay process is enhanced when these organisms are associated. In contrast, the same bacteria and yeasts were inhibitory when combined with a brown-rot fungus.« less

Comparative transcriptome analysis of the CO2 sensing pathway via differential expression of carbonic anhydrase in Cryptococcus neoformans.

PubMed

Kim, Min Su; Ko, Young-Joon; Maeng, Shinae; Floyd, Anna; Heitman, Joseph; Bahn, Yong-Sun

2010-08-01

Carbon dioxide (CO(2)) sensing and metabolism via carbonic anhydrases (CAs) play pivotal roles in survival and proliferation of pathogenic fungi infecting human hosts from natural environments due to the drastic difference in CO(2) levels. In Cryptococcus neoformans, which causes fatal fungal meningoencephalitis, the Can2 CA plays essential roles during both cellular growth in air and sexual differentiation of the pathogen. However the signaling networks downstream of Can2 are largely unknown. To address this question, the present study employed comparative transcriptome DNA microarray analysis of a C. neoformans strain in which CAN2 expression is artificially controlled by the CTR4 (copper transporter) promoter. The P(CTR4)CAN2 strain showed growth defects in a CO(2)-dependent manner when CAN2 was repressed but resumed normal growth when CAN2 was overexpressed. The Can2-dependent genes identified by the transcriptome analysis include FAS1 (fatty acid synthase 1) and GPB1 (G-protein beta subunit), supporting the roles of Can2 in fatty acid biosynthesis and sexual differentiation. Cas3, a capsular structure designer protein, was also discovered to be Can2-dependent and yet was not involved in CO(2)-mediated capsule induction. Most notably, a majority of Can2-dependent genes were environmental stress-regulated (ESR) genes. Supporting this, the CAN2 overexpression strain was hypersensitive to oxidative and genotoxic stress as well as antifungal drugs, such as polyene and azole drugs, potentially due to defective membrane integrity. Finally, an oxidative stress-responsive Atf1 transcription factor was also found to be Can2-dependent. Atf1 not only plays an important role in diverse stress responses, including thermotolerance and antifungal drug resistance, but also represses melanin and capsule production in C. neoformans. In conclusion, this study provides insights into the comprehensive signaling networks orchestrated by CA/CO(2)-sensing pathways in pathogenic fungi.

Antimicrobial activity and biodiversity of endophytic fungi in Dendrobium devonianum and Dendrobium thyrsiflorum from Vietnam.

PubMed

Xing, Yong-Mei; Chen, Juan; Cui, Jin-Long; Chen, Xiao-Mei; Guo, Shun-Xing

2011-04-01

Endophytic fungi are rich in orchids and have great impacts on their host plants. 53 endophytes (30 isolates from Dendrobium devonianum and 23 endophytic fungi from D. thyrsiflorum) were isolated, respectively, from roots and stems of Dendrobium species. All the fungi were identified by way of morphological and/or molecular biological methods. 30 endophytic fungi in D. devonianum were categorized into 11 taxa and 23 fungal endophytes in D. thyrsiflorum were grouped into 11 genera, respectively. Fusarium was the dominant species of the two Dendrobium species in common. Antimicrobial activity of ethanol extract of fermentation broth of these fungi was explored using agar diffusion test. 10 endophytic fungi in D. devonianum and 11 in D. thyrsiflorum exhibited antimicrobial activity against at least one pathogenic bacterium or fungus among 6 pathogenic microbes (Escherichia coli, Bacillus subtilis, Staphylococcus aureus, Candida albicans, Cryptococcus neoformans, and Aspergillus fumigatus). Out of the fungal endophytes isolated from D. devonianum and D. thyrsiflorum, Phoma displayed strong inhibitory activity (inhibition zones in diameter >20 mm) against pathogens. Epicoccum nigrum from D. thyrsiflorum exhibited antibacterial activity even stronger than ampicillin sodium. Fusarium isolated from the two Dendrobium species was effective against the pathogenic bacterial as well as fungal pathogens. The study reinforced the assumption that endophytic fungi isolated from different Dendrobium species could be of potential antibacterial or antifungal resource.

The APSES family proteins in fungi: Characterizations, evolution and functions.

PubMed

Zhao, Yong; Su, Hao; Zhou, Jing; Feng, Huihua; Zhang, Ke-Qin; Yang, Jinkui

2015-08-01

The APSES protein family belongs to transcriptional factors of the basic helix-loop-helix (bHLH) class, the originally described members (APSES: Asm1p, Phd1p, Sok2p, Efg1p and StuAp) are used to designate this group of proteins, and they have been identified as key regulators of fungal development and other biological processes. APSES proteins share a highly conserved DNA-binding domain (APSES domain) of about 100 amino acids, whose central domain is predicted to form a typical bHLH structure. Besides APSES domain, several APSES proteins also contain additional domains, such as KilA-N and ankyrin repeats. In recent years, an increasing number of APSES proteins have been identified from diverse fungi, and they involve in numerous biological processes, such as sporulation, cellular differentiation, mycelial growth, secondary metabolism and virulence. Most fungi, including Aspergillus fumigatus, Aspergillus nidulans, Candida albicans, Fusarium graminearum, and Neurospora crassa, contain five APSES proteins. However, Cryptococcus neoformans only contains two APSES proteins, and Saccharomyces cerevisiae contains six APSES proteins. The phylogenetic analysis showed the APSES domains from different fungi were grouped into four clades (A, B, C and D), which is consistent with the result of homologous alignment of APSES domains using DNAman. The roles of APSES proteins in clade C have been studied in detail, while little is known about the roles of other APSES proteins in clades A, B and D. In this review, the biochemical properties and functional domains of APSES proteins are predicted and compared, and the phylogenetic relationship among APSES proteins from various fungi are analyzed based on the APSES domains. Moreover, the functions of APSES proteins in different fungi are summarized and discussed. Copyright © 2014 Elsevier Inc. All rights reserved.

How Cryptococcus interacts with the blood-brain barrier.

PubMed

Tseng, Hsiang-Kuang; Huang, Tseng-Yu; Wu, Alice Ying-Jung; Chen, Hsin-Hong; Liu, Chang-Pan; Jong, Ambrose

2015-01-01

Cryptococcus demonstrates predilection for invasion of the brain, but the mechanism by which Cryptococcus crosses the blood-brain barrier (BBB) to cause brain invasion is largely unknown. In order for Cryptococcus to cross the BBB, there must be a way to either cross human brain microvascular endothelial cells, which are the main constitute of the BBB, or go in between tight junctions. Recent evidence of human brain microvascular endothelial cell responses to transcellular brain invasions includes membrane rearrangements, intracellular signaling pathways and cytoskeletal activations. Several Cryptococcal genes related to the traversal of BBB have been identified, including CPS1, ITR1a, ITR3c, PLB1, MPR1, FNX1 and RUB1. In addition, Cryptococcus neoformans-derived microvesicles may contribute to cryptococcal brain invasion. Paracellularly, Cryptococcus may traverse across BBB using either routes utilizing plasmin, ammonia or macrophages in a Trojan horse mechanism.

Molecular typing of environmental Cryptococcus neoformans/C. gattii species complex isolates from Manaus, Amazonas, Brazil.

PubMed

Alves, Gleica Soyan Barbosa; Freire, Ana Karla Lima; Bentes, Amaury Dos Santos; Pinheiro, José Felipe de Souza; de Souza, João Vicente Braga; Wanke, Bodo; Matsuura, Takeshi; Jackisch-Matsuura, Ani Beatriz

2016-08-01

Cryptococcus neoformans and Cryptococcus gattii are the main causative agents of cryptococcosis, a systemic fungal disease that affects internal organs and skin, and which is acquired by inhalation of spores or encapsulated yeasts. It is currently known that the C. neoformans/C. gattii species complex has a worldwide distribution, however, some molecular types seem to prevail in certain regions. Few environmental studies of Cryptococcus have been conducted in the Brazilian Amazon. This is the first ecological study of the pathogenic fungi C. neoformans/C. gattii species complex in the urban area of Manaus, Amazonas, Brazil. A total of 506 samples from pigeon droppings (n = 191), captive bird droppings (n = 60) and tree hollows (n = 255) were collected from June 2012 to January 2014 at schools and public buildings, squares, pet shops, households, the zoo and the bus station. Samples were plated on niger seed agar (NSA) medium supplemented with chloramphenicol and incubated at 25°C for 5 days. Dark-brown colonies were isolated and tested for thermotolerance at 37°C, cycloheximide resistance and growth on canavanine-glycine-bromothymol blue agar. Molecular typing was done by PCR-RFLP. Susceptibility to the antifungal drugs amphotericin B, fluconazole, itraconazole and ketoconazole was tested using Etest(®) strips. In total, 13 positive samples were obtained: one tree hollow (C. gattiiVGII), nine pigeon droppings (C. neoformansVNI) and three captive bird droppings (C. neoformansVNI). The environmental cryptococcal isolates found in this study were of the same molecular types as those responsible for infections in Manaus. © 2016 Blackwell Verlag GmbH.

Mycological contamination in dental unit waterlines in Istanbul, Turkey

PubMed Central

Kadaifciler, Duygu Göksay; Ökten, Suzan; Sen, Burhan

2013-01-01

Studies on dental units (DUs) are conducted either for the prevention or the reduction of the density of bacterial contamination in dental unit waterlines (DUWLs). However, the existence of fungi in the these systems requires more attention. During dental treatment, direct contact with water contaminated with fungi such as Candida, Aspergillus, or inhalation of aerosols from high-speed drill may cause various respiratory infections, such as asthma, allergies, and wounds on mucose membranes, especially on immunocompromised patients and dentists. The aims of this study are to investigate the number and colonization of fungi in DUWLs in the city of Istanbul, Turkey. Water samples were collected from air-water syringes, high-speed drills, and inlet waters from 41 DUs. The aerobic mesophilic fungi count in high- speed drills was higher than inlet waters and air-water syringes. Non-sporulating fungi were found in 7 DUs. The isolated fungi were identified as Penicillium waksmanii, Cladosporium spp., Penicillium spp., Candida famata, Cryptococcus laurentii, Candida guilliermondii, Penicillium verrucosum, Aspergillus pseudoglaucus, Penicillium decumbens, and Acremonium sp. Some of these fungal genera are known as opportunistic pathogens that led to respiratory diseases such as allergic rhinits. This study shows the importance of regular control of mycological contamination on water at DUs. PMID:24516467

Cryptococcus neoformans sexual reproduction is controlled by a quorum sensing peptide.

PubMed

Tian, Xiuyun; He, Guang-Jun; Hu, Pengjie; Chen, Lei; Tao, Changyu; Cui, Ying-Lu; Shen, Lan; Ke, Weixin; Xu, Haijiao; Zhao, Youbao; Xu, Qijiang; Bai, Fengyan; Wu, Bian; Yang, Ence; Lin, Xiaorong; Wang, Linqi

2018-06-01

Bacterial quorum sensing is a well-characterized communication system that governs a large variety of collective behaviours. By comparison, quorum sensing regulation in eukaryotic microbes remains poorly understood, especially its functional role in eukaryote-specific behaviours, such as sexual reproduction. Cryptococcus neoformans is a prevalent fungal pathogen that has two defined sexual cycles (bisexual and unisexual) and is a model organism for studying sexual reproduction in fungi. Here, we show that the quorum sensing peptide Qsp1 serves as an important signalling molecule for both forms of sexual reproduction. Qsp1 orchestrates various differentiation and molecular processes, including meiosis, the hallmark of sexual reproduction. It activates bisexual mating, at least in part through the control of pheromone, a signal necessary for bisexual activation. Notably, Qsp1 also plays a major role in the intercellular regulation of unisexual initiation and coordination, in which pheromone is not strictly required. Through a multi-layered genetic screening approach, we identified the atypical zinc finger regulator Cqs2 as an important component of the Qsp1 signalling cascade during both bisexual and unisexual reproduction. The absence of Cqs2 eliminates the Qsp1-stimulated mating response. Together, these findings extend the range of behaviours governed by quorum sensing to sexual development and meiosis.

Vaccination with Recombinant Cryptococcus Proteins in Glucan Particles Protects Mice against Cryptococcosis in a Manner Dependent upon Mouse Strain and Cryptococcal Species.

PubMed

Specht, Charles A; Lee, Chrono K; Huang, Haibin; Hester, Maureen M; Liu, Jianhua; Luckie, Bridget A; Torres Santana, Melanie A; Mirza, Zeynep; Khoshkenar, Payam; Abraham, Ambily; Shen, Zu T; Lodge, Jennifer K; Akalin, Ali; Homan, Jane; Ostroff, Gary R; Levitz, Stuart M

2017-11-28

Development of a vaccine to protect against cryptococcosis is a priority given the enormous global burden of disease in at-risk individuals. Using glucan particles (GPs) as a delivery system, we previously demonstrated that mice vaccinated with crude Cryptococcus -derived alkaline extracts were protected against lethal challenge with Cryptococcus neoformans and Cryptococcus gattii The goal of the present study was to identify protective protein antigens that could be used in a subunit vaccine. Using biased and unbiased approaches, six candidate antigens (Cda1, Cda2, Cda3, Fpd1, MP88, and Sod1) were selected, recombinantly expressed in Escherichia coli , purified, and loaded into GPs. Three mouse strains (C57BL/6, BALB/c, and DR4) were then vaccinated with the antigen-laden GPs, following which they received a pulmonary challenge with virulent C. neoformans and C. gattii strains. Four candidate vaccines (GP-Cda1, GP-Cda2, GP-Cda3, and GP-Sod1) afforded a significant survival advantage in at least one mouse model; some vaccine combinations provided added protection over that seen with either antigen alone. Vaccine-mediated protection against C. neoformans did not necessarily predict protection against C. gattii Vaccinated mice developed pulmonary inflammatory responses that effectively contained the infection; many surviving mice developed sterilizing immunity. Predicted T helper cell epitopes differed between mouse strains and in the degree to which they matched epitopes predicted in humans. Thus, we have discovered cryptococcal proteins that make promising candidate vaccine antigens. Protection varied depending on the mouse strain and cryptococcal species, suggesting that a successful human subunit vaccine will need to contain multiple antigens, including ones that are species specific. IMPORTANCE The encapsulated fungi Cryptococcus neoformans and Cryptococcus gattii are responsible for nearly 200,000 deaths annually, mostly in immunocompromised individuals. An effective vaccine could substantially reduce the burden of cryptococcosis. However, a major gap in cryptococcal vaccine development has been the discovery of protective antigens to use in vaccines. Here, six cryptococcal proteins with potential as vaccine antigens were expressed recombinantly and purified. Mice were then vaccinated with glucan particle preparations containing each antigen. Of the six candidate vaccines, four protected mice from a lethal cryptococcal challenge. However, the degree of protection varied as a function of mouse strain and cryptococcal species. These preclinical studies identify cryptococcal proteins that could serve as candidate vaccine antigens and provide a proof of principle regarding the feasibility of protein antigen-based vaccines to protect against cryptococcosis. Copyright © 2017 Specht et al.

Interactions of Cryptococcus with Dendritic Cells

PubMed Central

Wozniak, Karen L.

2018-01-01

The fungal pathogens Cryptococcus neoformans and Cryptococcus gattii can cause life-threatening infections in immune compromised and immune competent hosts. These pathogens enter the host via inhalation, and respiratory tract innate immune cells such as dendritic cells (DCs) are one of the first host cells they encounter. The interactions between Cryptococcus and innate immune cells play a critical role in the progression of disease in the host. This review will focus specifically on the interactions between Cryptococcus and dendritic cells (DCs), including recognition/processing by DCs, effects of immune mediators on DC recruitment and activity, and the potential for DC vaccination against cryptococcosis. PMID:29543719

Interactions of Cryptococcus with Dendritic Cells.

PubMed

Wozniak, Karen L

2018-03-15

The fungal pathogens Cryptococcus neoformans and Cryptococcus gattii can cause life-threatening infections in immune compromised and immune competent hosts. These pathogens enter the host via inhalation, and respiratory tract innate immune cells such as dendritic cells (DCs) are one of the first host cells they encounter. The interactions between Cryptococcus and innate immune cells play a critical role in the progression of disease in the host. This review will focus specifically on the interactions between Cryptococcus and dendritic cells (DCs), including recognition/processing by DCs, effects of immune mediators on DC recruitment and activity, and the potential for DC vaccination against cryptococcosis.

The interaction of fungi with the environment orchestrated by RNAi.

PubMed

Villalobos-Escobedo, José Manuel; Herrera-Estrella, Alfredo; Carreras-Villaseñor, Nohemí

2016-01-01

The fungal kingdom has been key in the investigation of the biogenesis and function of small RNAs (sRNAs). The discovery of phenomena such as quelling in Neurospora crassa represents pioneering work in the identification of the main elements of the RNA interference (RNAi) machinery. Recent discoveries in the regulatory mechanisms in some yeast and filamentous fungi are helping us reach a deeper understanding of the transcriptional and post-transcriptional gene-silencing mechanisms involved in genome protection against viral infections, DNA damage and transposon activity. Although most of these mechanisms are reasonably well understood, their role in the physiology, response to the environment and interaction of fungi with other organisms had remained elusive. Nevertheless, studies in fungi such as Mucor circinelloides, Magnaporthe oryzae, Cryptococcus neoformans, Trichoderma atroviride, Botrytis cinerea and others have started to shed light on the relevance of the RNAi pathway. In these fungi gene regulation by RNAi is important for growth, reproduction, control of viral infections and transposon activity, as well as in the development of antibiotic resistance and interactions with their hosts. Moreover, the increasing number of reports of the discovery of microRNA-like RNAs in fungi under different conditions highlights the importance of fungi as models for understanding adaptation to the environment using regulation by sRNAs. The goal of this review is to provide the reader with an up-to-date overview of the importance of RNAi in the interaction of fungi with their environment. © 2016 by The Mycological Society of America.

Lichensphere: a protected natural microhabitat of the non-lichenised fungal communities living in extreme environments of Antarctica.

PubMed

Santiago, Iara F; Soares, Marco Aurélio; Rosa, Carlos A; Rosa, Luiz H

2015-11-01

We surveyed the diversity, distribution and ecology of non-lichenised fungal communities associated with the Antarctic lichens Usnea antarctica and Usnea aurantiaco-atra across Antarctica. The phylogenetic study of the 438 fungi isolates identified 74 taxa from 21 genera of Ascomycota, Basidiomycota and Zygomycota. The most abundant taxa were Pseudogymnoascus sp., Thelebolus sp., Antarctomyces psychrotrophicus and Cryptococcus victoriae, which are considered endemic and/or highly adapted to Antarctica. Thirty-five fungi may represent new and/or endemic species. The fungal communities displayed high diversity, richness and dominance indices; however, the similarity among the communities was variable. After discovering rich and diverse fungal communities composed of symbionts, decomposers, parasites and endemic and cold-adapted cosmopolitan taxa, we introduced the term "lichensphere". We hypothesised that the lichensphere may represent a protected natural microhabitat with favourable conditions able to help non-lichenised fungi and other Antarctic life forms survive and disperse in the extreme environments of Antarctica.

The Diversity and Distribution of Fungi on Residential Surfaces

PubMed Central

Adams, Rachel I.; Miletto, Marzia; Taylor, John W.; Bruns, Thomas D.

2013-01-01

The predominant hypothesis regarding the composition of microbial assemblages in indoor environments is that fungal assemblages are structured by outdoor air with a moderate contribution by surface growth, whereas indoor bacterial assemblages represent a mixture of bacteria entered from outdoor air, shed by building inhabitants, and grown on surfaces. To test the fungal aspect of this hypothesis, we sampled fungi from three surface types likely to support growth and therefore possible contributors of fungi to indoor air: drains in kitchens and bathrooms, sills beneath condensation-prone windows, and skin of human inhabitants. Sampling was done in replicated units of a university-housing complex without reported mold problems, and sequences were analyzed using both QIIME and the new UPARSE approach to OTU-binning, to the same result. Surfaces demonstrated a mycological profile similar to that of outdoor air from the same locality, and assemblages clustered by surface type. “Weedy” genera typical of indoor air, such as Cladosporium and Cryptococcus, were abundant on sills, as were a diverse set of fungi of likely outdoor origin. Drains supported more depauperate assemblages than the other surfaces and contained thermotolerant genera such as Exophiala, Candida, and Fusarium. Most surprising was the composition detected on residents’ foreheads. In addition to harboring Malassezia, a known human commensal, skin also possessed a surprising richness of non-resident fungi, including plant pathogens such as ergot (Claviceps purperea). Overall, fungal richness across indoor surfaces was high, but based on known autecologies, most of these fungi were unlikely to be growing on surfaces. We conclude that while some endogenous fungal growth on typical household surfaces does occur, particularly on drains and skin, all residential surfaces appear – to varying degrees – to be passive collectors of airborne fungi of putative outdoor origin, a view of the origins of the indoor microbiome quite different from bacteria. PMID:24223861

Long-term no-till: A major driver of fungal communities in dryland wheat cropping systems.

PubMed

Sharma-Poudyal, Dipak; Schlatter, Daniel; Yin, Chuntao; Hulbert, Scot; Paulitz, Timothy

2017-01-01

In the dryland Pacific Northwest wheat cropping systems, no-till is becoming more prevalent as a way to reduce soil erosion and fuel inputs. Tillage can have a profound effect on microbial communities and soilborne fungal pathogens, such as Rhizoctonia. We compared the fungal communities in long-term no-till (NT) plots adjacent to conventionally tilled (CT) plots, over three years at two locations in Washington state and one location in Idaho, US. We used pyrosequencing of the fungal ITS gene and identified 422 OTUs after rarefication. Fungal richness was higher in NT compared to CT, in two of the locations. Humicola nigrescens, Cryptococcus terreus, Cadophora spp. Hydnodontaceae spp., and Exophiala spp. were more abundant in NT, while species of Glarea, Coniochaetales, Mycosphaerella tassiana, Cryptococcus bhutanensis, Chaetomium perlucidum, and Ulocladium chartarum were more abundant in CT in most locations. Other abundant groups that did not show any trends were Fusarium, Mortierella, Penicillium, Aspergillus, and Macroventuria. Plant pathogens such as Rhizoctonia (Ceratobasidiaceae) were not abundant enough to see tillage differences, but Microdochium bolleyi, a weak root pathogen, was more abundant in NT. Our results suggest that NT fungi are better adapted at utilizing intact, decaying roots as a food source and may exist as root endophytes. CT fungi can utilize mature plant residues that are turned into the soil with tillage as pioneer colonizers, and then produce large numbers of conidia. But a larger proportion of the fungal community is not affected by tillage and may be niche generalists.

Polyphenolic substrates and dyes degradation by yeasts from 25 de Mayo/King George Island (Antarctica).

PubMed

Rovati, José I; Pajot, Hipólito F; Ruberto, Lucas; Mac Cormack, Walter; Figueroa, Lucía I C

2013-11-01

Antarctica offers a range of extreme climatic conditions, such as low temperatures, high solar radiation and low nutrient availability, and constitutes one of the harshest environments on Earth. Despite that, it has been successfully colonized by ’cold-loving’ fungi, which play a key role in decomposition cycles in cold ecosystems. However, knowledge about the ecological role of yeasts in nutrient or organic matter recycling/mineralization remains highly fragmentary. The aim of this work was to study the yeast microbiota in samples collected on 25 de Mayo/King George Island regarding the scope of their ability to degrade polyphenolic substrates such as lignin and azo dyes. Sixty-one yeast isolates were obtained from 37 samples, including soil, rocks, wood and bones. Molecular analyses based on rDNA sequences revealed that 35 yeasts could be identified at the species level and could be classified in the genera Leucosporidiella, Rhodotorula, Cryptococcus, Bullera and Candida. Cryptococcus victoriae was by far the most ubiquitous species. In total, 33% of the yeast isolates examined showed significant activity for dye decolorization, 25% for laccase activity and 38% for ligninolytic activity. Eleven yeasts did not show positive activity in any of the assays performed and no isolates showed positive activity across all tested substrates. A high diversity of yeasts were isolated in this work, possibly including undescribed species and conspicuous Antarctic yeasts, most of them belonging to oligotrophic, slow-growing and metabolically diverse basidiomycetous genera.

Changes in the composition of intestinal fungi and their role in mice with dextran sulfate sodium-induced colitis.

PubMed

Qiu, Xinyun; Zhang, Feng; Yang, Xi; Wu, Na; Jiang, Weiwei; Li, Xia; Li, Xiaoxue; Liu, Yulan

2015-05-27

Intestinal fungi are increasingly believed to greatly influence gut health. However, the effects of fungi on intestinal inflammation and on gut bacterial constitution are not clear. Here, based on pyrosequencing method, we reveal that fungal compositions vary in different intestinal segments (ileum, cecum, and colon), prefer different colonization locations (mucosa and feces), and are remarkably changed during intestinal inflammation in dextran sulfate sodium (DSS)-colitis mouse models compare to normal controls: Penicillium, Wickerhamomyces, Alternaria, and Candida are increased while Cryptococcus, Phialemonium, Wallemia and an unidentified Saccharomycetales genus are decreased in the guts of DSS-colitis mice. Fungi-depleted mice exhibited aggravated acute DSS-colitis associated with gain of Hallella, Barnesiella, Bacteroides, Alistipes, and Lactobacillus and loss of butyrate-producing Clostridium XIVa, and Anaerostipes compare with normal control. In contrast, bacteria-depleted mice show attenuated acute DSS-colitis. Mice with severely chronic recurrent DSS-colitis show increased plasma (1,3)-β-D-glucan level and fungal translocation into the colonic mucosa, mesenteric lymph nodes and spleen. This work demonstrate the different roles of fungi in acute and chronic recurrent colitis: They are important counterbalance to bacteria in maintaining intestinal micro-ecological homeostasis and health in acutely inflamed intestines, but can harmfully translocate into abnormal sites and could aggravate disease severity in chronic recurrent colitis.

Yeast diversity associated to sediments and water from two Colombian artificial lakes

PubMed Central

Silva-Bedoya, L.M.; Ramírez-Castrillón, M.; Osorio-Cadavid, E.

2014-01-01

In Colombia, knowledge of the yeast and yeast-like fungi community is limited because most studies have focused on species with clinical importance. Sediments and water represent important habitats for the study of yeast diversity, especially for yeast species with industrial, biotechnological, and bioremediation potential. The main purpose of this study was to identify and compare the diversity of yeast species associated with sediment and water samples from two artificial lakes in Universidad del Valle (Cali-Colombia). Yeast samplings were performed from fifteen sediment samples and ten water samples. Grouping of similar isolates was initially based on colony and cell morphology, which was then complemented by micro/mini satellite primed PCR banding pattern analysis by using GTG5 as single primer. A representative isolate for each group established was chosen for D1/D2 domain sequencing and identification. In general, the following yeast species were identified: Candida albicans, Candida diversa, Candida glabrata, Candida pseudolambica, Cryptococcus podzolicus, Cryptococcus rajasthanensis, Cryptococcus laurentii, Williopsis saturnus, Hanseniaspora thailandica, Hanseniaspora uvarum, Rhodotorula mucilaginosa, Saccharomyces cerevisiae, Torulaspora delbrueckii, Torulaspora pretoriensis, Tricosporon jirovecii, Trichosporon laibachii and Yarrowia lypolitica. Two possible new species were also found, belonging to the Issatchenkia sp. and Bullera sp. genera. In conclusion, the lakes at the Universidad del Valle campus have significant differences in yeast diversity and species composition between them. PMID:24948924

A Family of Secretory Proteins Is Associated with Different Morphotypes in Cryptococcus neoformans.

PubMed

Gyawali, Rachana; Upadhyay, Srijana; Way, Joshua; Lin, Xiaorong

2017-03-01

Cryptococcus neoformans , an opportunistic human fungal pathogen, can undergo a yeast-to-hypha transition in response to environmental cues. This morphological transition is associated with changes in the expression of cell surface proteins. The Cryptococcus cell surface and secreted protein Cfl1 was the first identified adhesin in the Basidiomycota. Cfl1 has been shown to regulate morphology, biofilm formation, and intercellular communication. Four additional homologs of CFL1 are harbored by the Cryptococcus genome: DHA1 , DHA2 , CPL1 , and CFL105 The common features of this gene family are the conserved C-terminal SIGC domain and the presence of an N-terminal signal peptide. We found that all these Cfl1 homolog proteins are indeed secreted extracellularly. Interestingly, some of these secretory proteins display cell type-specific expression patterns: Cfl1 is hypha specific, Dha2 is yeast specific, and Dha1 (delayed hypersensitivity antigen 1) is expressed in all cell types but is particularly enriched at basidia. Interestingly, Dha1 is induced by copper limitation and suppressed by excessive copper in the medium. This study further attests to the physiological heterogeneity of the Cryptococcus mating colony, which is composed of cells with heterogeneous morphotypes. The differential expression of these secretory proteins contributes to heterogeneity, which is beneficial for the fungus to adapt to changing environments. IMPORTANCE Heterogeneity in physiology and morphology is an important bet-hedging strategy for nonmobile microbes such as fungi to adapt to unpredictable environmental changes. Cryptococcus neoformans , a ubiquitous basidiomycetous fungus, is known to switch from the yeast form to the hypha form during sexual development. However, in a mating colony, only a subset of yeast cells switch to hyphae, and only a fraction of the hyphal subpopulation will develop into fruiting bodies, where meiosis and sporulation occur. Here, we investigated a basidiomycete-specific secretory protein family. We found that some of these proteins are cell type specific, thus contributing to the heterogeneity of a mating colony. Our study also demonstrates the importance of examining the protein expression pattern at the individual-cell level in addition to population gene expression profiling for the investigation of a heterogeneous community. Copyright © 2017 American Society for Microbiology.

Cellulose utilization in forest litter and soil: identification of bacterial and fungal decomposers.

PubMed

Stursová, Martina; Zifčáková, Lucia; Leigh, Mary Beth; Burgess, Robert; Baldrian, Petr

2012-06-01

Organic matter decomposition in the globally widespread coniferous forests has an important role in the carbon cycle, and cellulose decomposition is especially important in this respect because cellulose is the most abundant polysaccharide in plant litter. Cellulose decomposition was 10 times faster in the fungi-dominated litter of Picea abies forest than in the bacteria-dominated soil. In the soil, the added (13)C-labelled cellulose was the main source of microbial respiration and was preferentially accumulated in the fungal biomass and cellulose induced fungal proliferation. In contrast, in the litter, bacterial biomass showed higher labelling after (13)C-cellulose addition and bacterial biomass increased. While 80% of the total community was represented by 104-106 bacterial and 33-59 fungal operational taxonomic units (OTUs), 80% of the cellulolytic communities of bacteria and fungi were only composed of 8-18 highly abundant OTUs. Both the total and (13)C-labelled communities differed substantially between the litter and soil. Cellulolytic bacteria in the acidic topsoil included Betaproteobacteria, Bacteroidetes and Acidobacteria, whereas these typically found in neutral soils were absent. Most fungal cellulose decomposers belonged to Ascomycota; cellulolytic Basidiomycota were mainly represented by the yeasts Trichosporon and Cryptococcus. Several bacteria and fungi demonstrated here to derive their carbon from cellulose were previously not recognized as cellulolytic. © 2012 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.

Fungi associated with rocks of the Atacama Desert: taxonomy, distribution, diversity, ecology and bioprospection for bioactive compounds.

PubMed

Gonçalves, Vívian N; Cantrell, Charles L; Wedge, David E; Ferreira, Mariana C; Soares, Marco Aurélio; Jacob, Melissa R; Oliveira, Fabio S; Galante, Douglas; Rodrigues, Fabio; Alves, Tânia M A; Zani, Carlos L; Junior, Policarpo A S; Murta, Silvane; Romanha, Alvaro J; Barbosa, Emerson C; Kroon, Erna G; Oliveira, Jaquelline G; Gomez-Silva, Benito; Galetovic, Alexandra; Rosa, Carlos A; Rosa, Luiz H

2016-01-01

This study assessed the diversity of cultivable rock-associated fungi from Atacama Desert. A total of 81 fungal isolates obtained were identified as 29 Ascomycota taxa by sequencing different regions of DNA. Cladosporium halotolerans, Penicillium chrysogenum and Penicillium cf. citrinum were the most frequent species, which occur at least in four different altitudes. The diversity and similarity indices ranged in the fungal communities across the latitudinal gradient. The Fisher-α index displayed the higher values for the fungal communities obtained from the siltstone and fine matrix of pyroclastic rocks with finer grain size, which are more degraded. A total of 23 fungal extracts displayed activity against the different targets screened. The extract of P. chrysogenum afforded the compounds α-linolenic acid and ergosterol endoperoxide, which were active against Cryptococcus neoformans and methicillin-resistance Staphylococcus aureus respectively. Our study represents the first report of a new habitat of fungi associated with rocks of the Atacama Desert and indicated the presence of interesting fungal community, including species related with saprobes, parasite/pathogen and mycotoxigenic taxa. The geological characteristics of the rocks, associated with the presence of rich resident/resilient fungal communities suggests that the rocks may provide a favourable microenvironment fungal colonization, survival and dispersal in extreme conditions. © 2015 Society for Applied Microbiology and John Wiley & Sons Ltd.

Environmental isolation, biochemical identification, and antifungal drug susceptibility of Cryptococcus species.

PubMed

Teodoro, Valter Luis Iost; Gullo, Fernanda Patrícia; Sardi, Janaína de Cássia Orlandi; Torres, Edson Maria; Fusco-Almeida, Ana Marisa; Mendes-Giannini, Maria José Soares

2013-01-01

The incidence of opportunistic fungal infections has increased in recent years and is considered an important public health problem. Among systemic and opportunistic mycoses, cryptococcosis is distinguished by its clinical importance due to the increased risk of infection in individuals infected by human immunodeficiency virus. To determine the occurrence of pathogenic Cryptococcus in pigeon excrement in the City of Araraquara, samples were collected from nine environments, including state and municipal schools, abandoned buildings, parks, and a hospital. The isolates were identified using classical tests, and susceptibility testing for the antifungal drugs (fluconazole, itraconazole, voriconazole, and amphotericin B) independently was also performed. After collection, the excrement samples were plated on Niger agar and incubated at room temperature. A total of 87 bird dropping samples were collected, and 66.6% were positive for the genus Cryptococcus. The following species were identified: Cryptococcus neoformans (17.2%), Cryptococcus gattii (5.2%), Cryptococcus ater (3.5%), Cryptococcus laurentti (1.7%), and Cryptococcus luteolus (1.7%). A total of 70.7% of the isolates were not identified to the species level and are referred to as Cryptococcus spp. throughout the manuscript. Although none of the isolates demonstrated resistance to antifungal drugs, the identification of infested areas, the proper control of birds, and the disinfection of these environments are essential for the epidemiological control of cryptococcosis.

Central Role of the Trehalose Biosynthesis Pathway in the Pathogenesis of Human Fungal Infections: Opportunities and Challenges for Therapeutic Development

PubMed Central

Thammahong, Arsa; Puttikamonkul, Srisombat; Perfect, John R.; Brennan, Richard G.

2017-01-01

SUMMARY Invasive fungal infections cause significant morbidity and mortality in part due to a limited antifungal drug arsenal. One therapeutic challenge faced by clinicians is the significant host toxicity associated with antifungal drugs. Another challenge is the fungistatic mechanism of action of some drugs. Consequently, the identification of fungus-specific drug targets essential for fitness in vivo remains a significant goal of medical mycology research. The trehalose biosynthetic pathway is found in a wide variety of organisms, including human-pathogenic fungi, but not in humans. Genes encoding proteins involved in trehalose biosynthesis are mechanistically linked to the metabolism, cell wall homeostasis, stress responses, and virulence of Candida albicans, Cryptococcus neoformans, and Aspergillus fumigatus. While there are a number of pathways for trehalose production across the tree of life, the TPS/TPP (trehalose-6-phosphate synthase/trehalose-6-phosphate phosphatase) pathway is the canonical pathway found in human-pathogenic fungi. Importantly, data suggest that proteins involved in trehalose biosynthesis play other critical roles in fungal metabolism and in vivo fitness that remain to be fully elucidated. By further defining the biology and functions of trehalose and its biosynthetic pathway components in pathogenic fungi, an opportunity exists to leverage this pathway as a potent antifungal drug target. The goal of this review is to cover the known roles of this important molecule and its associated biosynthesis-encoding genes in the human-pathogenic fungi studied to date and to employ these data to critically assess the opportunities and challenges facing development of this pathway as a therapeutic target. PMID:28298477

Plants from Lamiaceae family as source of antifungal molecules in humane and veterinary medicine.

PubMed

Waller, Stefanie Bressan; Cleff, Marlete Brum; Serra, Emanoele Figueiredo; Silva, Anna Luiza; Gomes, Angelita Dos Reis; de Mello, João Roberto Braga; de Faria, Renata Osório; Meireles, Mário Carlos Araújo

2017-03-01

This work aimed to review the main plants of Lamiaceae family with activity against pathogenic fungi of medical and veterinary interest. Published studies in the main international databases between January 2002 and June 2016 showed that 55 botanical species belonging to 27 genus presented antifungal activity in different forms of extractions, mainly essential oils. Pathogenic fungi of Aspergillus spp., Candida spp., Malassezia spp., Cryptococcus spp., Sporothrix spp., Microsporum spp., Trichophyton spp. and Epidermophyton spp. genus were in vitro sensitive to several plants of Lamiaceae family. Chemical molecules isolated were described as promising use as antifungals in mycoses, highlighting estragole, 1,8-cineole, terpineol-4, γ-terpinene, among others. However, it should be alert to need of universal standardization in the laboratories tests with natural products. Copyright © 2017 Elsevier Ltd. All rights reserved.

Sesquiterpene-derived metabolites from the deep water marine sponge Poecillastra sollasi.

PubMed

Killday, K B; Longley, R; McCarthy, P J; Pomponi, S A; Wright, A E; Neale, R F; Sills, M A

1993-04-01

Six sesquiterpene-derived compounds, 1-6, which we call sollasins a-f, have been isolated from a deep water specimen of the sponge Poecillastra sollasi. The structures were elucidated by comparison of spectral data to related metabolites and confirmed using spectroscopic methods. The compounds inhibit the growth of the pathogenic fungi Candida albicans and Cryptococcus neoformans and the P-388 and A-549 tumor cell lines. Compounds 3 and 4 show weak inhibition of binding of [125I] angiotensin II to rat aorta smooth muscle cell membranes.

Cryptococcus socialis sp. nov. and Cryptococcus consortionis sp. nov., Antarctic basidioblastomycetes

NASA Technical Reports Server (NTRS)

Vishniac, H. S.

1985-01-01

New yeasts from the Ross Desert (dry valley area) of Antarctica include Cryptococcus socialis sp. nov. and Cryptococcus consortionis sp. nov. Cryptococcus socialis MYSW A801-3aY1 (= ATCC 56685) requires no vitamins, assimilates L-arabinose, cellobiose, D-glucuronate, maltose, melezitose, raffinose, soluble starch, sucrose, and trehalose, and may be distinguished from all other basidioblastomycetes by the combination of amylose production, cellobiose assimilation, and failure to utilize nitrate, D-galactose, myo-inositol, and mannitol. Its guanine-plus-cytosine content is 56 mol%. Cryptococcus consortionis MYSW A801-3aY92 (= ATCC 56686) requires thiamine, assimilates L-arabinose, D-glucuronate, 2-ketogluconate, salicin, succinate, sucrose, trehalose, and D-xylose, and may be distinguished from all other basidioblastomycetes by the combination of amylose production and failure to utilize nitrate, cellobiose, D-galactose, myo-inositol, and mannitol. Its guanine-plus-cytosine content is 56 mol%.

Antibacterial and antifungal activities from Siamese crocodile blood.

PubMed

Leelawongtawon, Ratree; Siruntawineti, Jindawan; Chaeychomsri, Win; Sattaponpan, Chisanucha

2010-12-01

To evaluate the in vitro antimicrobial activity of the Siamese crocodile blood against bacteria and fungi. Thirty Siamese crocodile blood samples including freeze dried whole blood (FDWB), fresh serum (FS), and freeze dried serum (FDS) were evaluated for antimicrobial susceptibility and MIC values against ATCC-registered strains of nine bacterial species and two fungal species and one fungus isolated from a clinical specimen, by using the standard broth microdilution method and a modified resazurin microtiter plate assay. The result showed that FS (80 mg/ml) and FDS (100 mg/ml) inhibited Gram negative bacteria including Enterobacter aerogenes ATCC 13048, Escherichia coli ATCC 25922, Klebsiella pneumoniae ATCC 27736, Salmonella typhimurium ATCC 13311 and Pseudomonas aeruginosa ATCC 27853 with the susceptibility rate at 23.30%, 10.00%, 40.00%, 70.00%, and 86.67%, respectively for FS, and 30.00%, 10.00%, 43.33%, 76.67% and 90.00%, respectively for FDS. The MIC and MBC were in the range of 12.50-100.00 mg/ml and 25.00-100.00 mg/m1 respectively. FS and FDS also inhibited Cryptococcus neoformans 250309 and Aspergillus niger with the susceptibility rate at 90.00% and 80.00%, respectively for FS and 100.00% and 83.33%, respectively for FDS. The MIC was in the range of 25.00-100.00 mg/ml. However, FS and FDS did not inhibit Gram positive bacteria and did not kill fungi. FDWB (100 mg/ml) could neither inhibit bacteria nor fungi. FS and FDS from Siamese crocodile exhibited potential antibacterial and antifungal activities.

Tenebrio molitor (Coleoptera: Tenebrionidae) as an alternative host to study fungal infections.

PubMed

de Souza, Patrícia Canteri; Morey, Alexandre Tadachi; Castanheira, Gabriel Marcondes; Bocate, Karla Paiva; Panagio, Luciano Aparecido; Ito, Fabio Augusto; Furlaneto, Márcia Cristina; Yamada-Ogatta, Sueli Fumie; Costa, Idessânia Nazareth; Mora-Montes, Hector Manuel; Almeida, Ricardo Sergio

2015-11-01

Models of host–pathogen interactions are crucial for the analysis of microbial pathogenesis. In this context, invertebrate hosts, including Drosophila melanogaster (fruit fly), Caenorhabditis elegans (nematode) and Galleria mellonella (moth), have been used to study the pathogenesis of fungi and bacteria. Each of these organisms offers distinct benefits in elucidating host–pathogen interactions. In this study,we present a newinvertebrate infection model to study fungal infections: the Tenebrio molitor (beetle) larvae. Here we performed T. molitor larvae infection with one of two important fungal human pathogens, Candida albicans or Cryptococcus neoformans, and analyzed survival curves and larva infected tissues.We showed that increasing concentrations of inoculum of both fungi resulted in increased mortality rates, demonstrating the efficiency of the method to evaluate the virulence of pathogenic yeasts. Additionally, following 12 h post-infection, C. albicans formsmycelia, spreading its hyphae through the larva tissue,whilst GMS stain enabled the visualization of C. neoformans yeast and theirmelanin capsule. These larvae are easier to cultivate in the laboratory than G. mellonella larvae, and offer the same benefits. Therefore, this insect model could be a useful alternative tool to screen clinical pathogenic yeast strainswith distinct virulence traits or different mutant strains.

FUNGI ISOLATED FROM THE EXCRETA OF WILD BIRDS IN SCREENING CENTERS IN PELOTAS, RS, BRAZIL

PubMed Central

Mendes, Josiara Furtado; Albano, Ana Paula Neuschrank; Coimbra, Marco Antônio A.; de Ferreira, Gracialda Ferreira; Gonçalves, Carolina Lambrecht; Nascente, Patrícia da Silva; de Mello, João Roberto Braga

2014-01-01

The identification of the fungal species belonging to the healthy microflora in animals is a precondition for the recognition of pathological processes causing them. The aim of this study was to investigate the presence of potentially pathogenic fungi in the feces of wild birds collected in Screening Centers. Samples were collected from the feces of 50 cages with different species of birds. The samples were processed according to the modified method STAIB and the plates incubated at 32 °C for up to ten days with daily observation for detection of fungal growth. The isolation of the following species was observed: Malassezia pachydermatis, Candida albicans, C. famata, C. guilliermondii, C. sphaerica, C. globosa, C. catenulata, C. ciferri, C. intermedia, Cryptococcus laurentii, Trichosporon asahii, Geotrichum klebahnii, Aspergillus spp., A. niger and Penicillium spp. Knowing the character of some opportunistic fungi is important in identifying them, facilitating the adoption of preventive measures, such as proper cleaning of cages, since the accumulation of excreta may indicate a risk for both health professionals and centers for screening public health. PMID:25351548

The radioprotective properties of fungal melanin are a function of its chemical composition, stable radical presence and spatial arrangement.

PubMed

Dadachova, Ekaterina; Bryan, Ruth A; Howell, Robertha C; Schweitzer, Andrew D; Aisen, Philip; Nosanchuk, Joshua D; Casadevall, Arturo

2008-04-01

Melanized microorganisms are often found in environments with very high background radiation levels such as in nuclear reactor cooling pools and the destroyed reactor in Chernobyl. These findings and the laboratory observations of the resistance of melanized fungi to ionizing radiation suggest a role for this pigment in radioprotection. We hypothesized that the radioprotective properties of melanin in microorganisms result from a combination of physical shielding and quenching of cytotoxic free radicals. We have investigated the radioprotective properties of melanin by subjecting the human pathogenic fungi Cryptococcus neoformans and Histoplasma capsulatum in their melanized and non-melanized forms to sublethal and lethal doses of radiation of up to 8 kGy. The contribution of chemical composition, free radical presence, spatial arrangement, and Compton scattering to the radioprotective properties of melanin was investigated by high-performance liquid chromatography, electron spin resonance, transmission electron microscopy, and autoradiographic techniques. Melanin protected fungi against ionizing radiation and its radioprotective properties were a function of its chemical composition, free radical quenching, and spherical spatial arrangement.

Advances in the diagnosis and treatment of fungal infections of the CNS.

PubMed

Schwartz, Stefan; Kontoyiannis, Dimitrios P; Harrison, Thomas; Ruhnke, Markus

2018-04-01

Fungal infections of the CNS are challenging to treat and their optimal management requires knowledge of their epidemiology, host characteristics, diagnostic criteria, and therapeutic options. Aspergillus and Cryptococcus species predominate among fungal infections of the CNS. Most of these fungi are ubiquitous, but some have restricted geographical distribution. Fungal infections of the CNS usually originate from primary sites outside the CNS (eg, fungal pneumonia) or occur after inoculation (eg, invasive procedures). Most patients with these infections have immunodeficiencies, but immunocompetent individuals can also be infected through heavy exposure. The infecting fungi can be grouped into moulds, yeasts, and dimorphic fungi. Substantial progress has been made with new diagnostic approaches and the introduction of novel antifungal drugs, but fungal infections of the CNS are frequently lethal because of diagnostic delays, impaired drug penetration, resistance to antifungal treatments, and inadequate restoration of immune function. To improve outcomes, future research should advance diagnostic methods (eg, molecular detection and fungus identification), develop antifungal compounds with enhanced CNS-directed efficacy, and further investigate crucial host defence mechanisms. Copyright © 2018 Elsevier Ltd. All rights reserved.

Comparison of selective staining of fungi in paraffin sections by light microscopy, SEM and BEI

DOE Office of Scientific and Technical Information (OSTI.GOV)

Berman, E.L.; Laudate, A.; Carter, H.W.

Paraffin-embedded sections from human tissues with fungi or organisms classified with fungi were studied by light microscopy (LM), scanning electron microscopy (SEM), and the backscatter electron imaging (BEI) mode of the SEM. The fungal organisms selected for study were those familiar to the pathologist on the basis of their appearance in paraffin-embedded material stained with the Gomori-Grocott Chromic Acid Methenamine Silver Stain (GMS). The organisms were Actinomyces, Rhizopus, Cryptococcus, Histoplasma capsulatum, and Coccidia imitis. Sections were stained with the GMS Stain and/or the Becker modification of the GMS Stain (BGMS) and examined in the secondary electron imaging mode (SEI) andmore » BEI mode with an annular backscatter electron detector. This silver staining technique accentuated the wall of fungal organisms, in the backscatter mode. Depending on the fungal organism and type of silver stain employed, the GMS seemed the preferable stain. The advantages of SEM over LM were greater depth of focus and potential range of magnifications. BEI may also be used in conjunction with LM stain for microorganisms to establish their presence.« less

Changes in the composition of intestinal fungi and their role in mice with dextran sulfate sodium-induced colitis

PubMed Central

Qiu, Xinyun; Zhang, Feng; Yang, Xi; Wu, Na; Jiang, Weiwei; Li, Xia; Li, Xiaoxue; Liu, Yulan

2015-01-01

Intestinal fungi are increasingly believed to greatly influence gut health. However, the effects of fungi on intestinal inflammation and on gut bacterial constitution are not clear. Here, based on pyrosequencing method, we reveal that fungal compositions vary in different intestinal segments (ileum, cecum, and colon), prefer different colonization locations (mucosa and feces), and are remarkably changed during intestinal inflammation in dextran sulfate sodium (DSS)-colitis mouse models compare to normal controls: Penicillium, Wickerhamomyces, Alternaria, and Candida are increased while Cryptococcus, Phialemonium, Wallemia and an unidentified Saccharomycetales genus are decreased in the guts of DSS-colitis mice. Fungi-depleted mice exhibited aggravated acute DSS-colitis associated with gain of Hallella, Barnesiella, Bacteroides, Alistipes, and Lactobacillus and loss of butyrate-producing Clostridium XIVa, and Anaerostipes compare with normal control. In contrast, bacteria-depleted mice show attenuated acute DSS-colitis. Mice with severely chronic recurrent DSS-colitis show increased plasma (1,3)-β-D-glucan level and fungal translocation into the colonic mucosa, mesenteric lymph nodes and spleen. This work demonstrate the different roles of fungi in acute and chronic recurrent colitis: They are important counterbalance to bacteria in maintaining intestinal micro-ecological homeostasis and health in acutely inflamed intestines, but can harmfully translocate into abnormal sites and could aggravate disease severity in chronic recurrent colitis. PMID:26013555

DNA Mutations Mediate Microevolution between Host-Adapted Forms of the Pathogenic Fungus Cryptococcus neoformans

PubMed Central

Magditch, Denise A.; Liu, Tong-Bao; Xue, Chaoyang; Idnurm, Alexander

2012-01-01

The disease cryptococcosis, caused by the fungus Cryptococcus neoformans, is acquired directly from environmental exposure rather than transmitted person-to-person. One explanation for the pathogenicity of this species is that interactions with environmental predators select for virulence. However, co-incubation of C. neoformans with amoeba can cause a “switch” from the normal yeast morphology to a pseudohyphal form, enabling fungi to survive exposure to amoeba, yet conversely reducing virulence in mammalian models of cryptococcosis. Like other human pathogenic fungi, C. neoformans is capable of microevolutionary changes that influence the biology of the organism and outcome of the host-pathogen interaction. A yeast-pseudohyphal phenotypic switch also happens under in vitro conditions. Here, we demonstrate that this morphological switch, rather than being under epigenetic control, is controlled by DNA mutation since all pseudohyphal strains bear mutations within genes encoding components of the RAM pathway. High rates of isolation of pseudohyphal strains can be explained by the physical size of RAM pathway genes and a hypermutator phenotype of the strain used in phenotypic switching studies. Reversion to wild type yeast morphology in vitro or within a mammalian host can occur through different mechanisms, with one being counter-acting mutations. Infection of mice with RAM mutants reveals several outcomes: clearance of the infection, asymptomatic maintenance of the strains, or reversion to wild type forms and progression of disease. These findings demonstrate a key role of mutation events in microevolution to modulate the ability of a fungal pathogen to cause disease. PMID:23055925

Long-term no-till: A major driver of fungal communities in dryland wheat cropping systems

PubMed Central

Sharma-Poudyal, Dipak; Schlatter, Daniel; Yin, Chuntao; Hulbert, Scot

2017-01-01

In the dryland Pacific Northwest wheat cropping systems, no-till is becoming more prevalent as a way to reduce soil erosion and fuel inputs. Tillage can have a profound effect on microbial communities and soilborne fungal pathogens, such as Rhizoctonia. We compared the fungal communities in long-term no-till (NT) plots adjacent to conventionally tilled (CT) plots, over three years at two locations in Washington state and one location in Idaho, US. We used pyrosequencing of the fungal ITS gene and identified 422 OTUs after rarefication. Fungal richness was higher in NT compared to CT, in two of the locations. Humicola nigrescens, Cryptococcus terreus, Cadophora spp. Hydnodontaceae spp., and Exophiala spp. were more abundant in NT, while species of Glarea, Coniochaetales, Mycosphaerella tassiana, Cryptococcus bhutanensis, Chaetomium perlucidum, and Ulocladium chartarum were more abundant in CT in most locations. Other abundant groups that did not show any trends were Fusarium, Mortierella, Penicillium, Aspergillus, and Macroventuria. Plant pathogens such as Rhizoctonia (Ceratobasidiaceae) were not abundant enough to see tillage differences, but Microdochium bolleyi, a weak root pathogen, was more abundant in NT. Our results suggest that NT fungi are better adapted at utilizing intact, decaying roots as a food source and may exist as root endophytes. CT fungi can utilize mature plant residues that are turned into the soil with tillage as pioneer colonizers, and then produce large numbers of conidia. But a larger proportion of the fungal community is not affected by tillage and may be niche generalists. PMID:28898288

Carbon dioxide is a powerful inducer of monokaryotic hyphae and spore development in Cryptococcus gattii and carbonic anhydrase activity is dispensable in this dimorphic transition.

PubMed

Ren, Ping; Chaturvedi, Vishnu; Chaturvedi, Sudha

2014-01-01

Cryptococcus gattii is unique among human pathogenic fungi with specialized ecological niche on trees. Since leaves concentrate CO2, we investigated the role of this gaseous molecule in C. gattii biology and virulence. We focused on the genetic analyses of β-carbonic anhydrase (β-CA) encoded by C. gattii CAN1 and CAN2 as later is critical for CO2 sensing in a closely related pathogen C. neoformans. High CO2 conditions induced robust development of monokaryotic hyphae and spores in C. gattii. Conversely, high CO2 completely repressed hyphae development in sexual mating. Both CAN1 and CAN2 were dispensable for CO2 induced morphogenetic transitions. However, C. gattii CAN2 was essential for growth in ambient air similar to its reported role in C. neoformans. Both can1 and can2 mutants retained full pathogenic potential in vitro and in vivo. These results provide insight into C. gattii adaptation for arboreal growth and production of infectious propagules by β-CA independent mechanism(s).

Carbon Dioxide is a Powerful Inducer of Monokaryotic Hyphae and Spore Development in Cryptococcus gattii and Carbonic Anhydrase Activity is Dispensable in This Dimorphic Transition

PubMed Central

Ren, Ping; Chaturvedi, Vishnu; Chaturvedi, Sudha

2014-01-01

Cryptococcus gattii is unique among human pathogenic fungi with specialized ecological niche on trees. Since leaves concentrate CO2, we investigated the role of this gaseous molecule in C. gattii biology and virulence. We focused on the genetic analyses of β-carbonic anhydrase (β-CA) encoded by C. gattii CAN1 and CAN2 as later is critical for CO2 sensing in a closely related pathogen C. neoformans. High CO2 conditions induced robust development of monokaryotic hyphae and spores in C. gattii. Conversely, high CO2 completely repressed hyphae development in sexual mating. Both CAN1 and CAN2 were dispensable for CO2 induced morphogenetic transitions. However, C. gattii CAN2 was essential for growth in ambient air similar to its reported role in C. neoformans. Both can1 and can2 mutants retained full pathogenic potential in vitro and in vivo. These results provide insight into C. gattii adaptation for arboreal growth and production of infectious propagules by β-CA independent mechanism(s). PMID:25478697

Disruption of de Novo Adenosine Triphosphate (ATP) Biosynthesis Abolishes Virulence in Cryptococcus neoformans.

PubMed

Blundell, Ross D; Williams, Simon J; Arras, Samantha D M; Chitty, Jessica L; Blake, Kirsten L; Ericsson, Daniel J; Tibrewal, Nidhi; Rohr, Jurgen; Koh, Y Q Andre E; Kappler, Ulrike; Robertson, Avril A B; Butler, Mark S; Cooper, Matthew A; Kobe, Bostjan; Fraser, James A

2016-09-09

Opportunistic fungal pathogens such as Cryptococcus neoformans are a growing cause of morbidity and mortality among immunocompromised populations worldwide. To address the current paucity of antifungal therapeutic agents, further research into fungal-specific drug targets is required. Adenylosuccinate synthetase (AdSS) is a crucial enzyme in the adeosine triphosphate (ATP) biosynthetic pathway, catalyzing the formation of adenylosuccinate from inosine monophosphate and aspartate. We have investigated the potential of this enzyme as an antifungal drug target, finding that loss of function results in adenine auxotrophy in C. neoformans, as well as complete loss of virulence in a murine model. Cryptococcal AdSS was expressed and purified in Escherichia coli and the enzyme's crystal structure determined, the first example of a structure of this enzyme from fungi. Together with enzyme kinetic studies, this structural information enabled comparison of the fungal enzyme with the human orthologue and revealed species-specific differences potentially exploitable via rational drug design. These results validate AdSS as a promising antifungal drug target and lay a foundation for future in silico and in vitro screens for novel antifungal compounds.

Nitrogen Metabolite Repression of Metabolism and Virulence in the Human Fungal Pathogen Cryptococcus neoformans

PubMed Central

Lee, I. Russel; Chow, Eve W. L.; Morrow, Carl A.; Djordjevic, Julianne T.; Fraser, James A.

2011-01-01

Proper regulation of metabolism is essential to maximizing fitness of organisms in their chosen environmental niche. Nitrogen metabolite repression is an example of a regulatory mechanism in fungi that enables preferential utilization of easily assimilated nitrogen sources, such as ammonium, to conserve resources. Here we provide genetic, transcriptional, and phenotypic evidence of nitrogen metabolite repression in the human pathogen Cryptococcus neoformans. In addition to loss of transcriptional activation of catabolic enzyme-encoding genes of the uric acid and proline assimilation pathways in the presence of ammonium, nitrogen metabolite repression also regulates the production of the virulence determinants capsule and melanin. Since GATA transcription factors are known to play a key role in nitrogen metabolite repression, bioinformatic analyses of the C. neoformans genome were undertaken and seven predicted GATA-type genes were identified. A screen of these deletion mutants revealed GAT1, encoding the only global transcription factor essential for utilization of a wide range of nitrogen sources, including uric acid, urea, and creatinine—three predominant nitrogen constituents found in the C. neoformans ecological niche. In addition to its evolutionarily conserved role in mediating nitrogen metabolite repression and controlling the expression of catabolic enzyme and permease-encoding genes, Gat1 also negatively regulates virulence traits, including infectious basidiospore production, melanin formation, and growth at high body temperature (39°–40°). Conversely, Gat1 positively regulates capsule production. A murine inhalation model of cryptococcosis revealed that the gat1Δ mutant is slightly more virulent than wild type, indicating that Gat1 plays a complex regulatory role during infection. PMID:21441208

Pitfalls in Serological Diagnosis of Cryptococcus gattii Infections.

PubMed

Tintelnot, Kathrin; Hagen, Ferry; Han, Chang Ok; Seibold, Michael; Rickerts, Volker; Boekhout, Teun

2015-11-01

The detection of cryptococcal antigen by latex agglutination tests (LATs), enzyme-linked immunoassays (ELISA), or lateral flow assay (LFA) is an important tool for diagnosis of a Cryptococcus infection. Cerebrospinal fluid and/or serum samples of 10 patients with cryptococcosis due to Cryptococcus gattii or a hybrid of Cryptococcus neoformans and C. gattii were examined by three LATs (the IMMY Latex-Crypto(®) test, the Pastorex(TM) Crypto Plus, and the Remel Cryptococcus Antigen Test Kit) and the LFA made by Immuno-Mycologics. LATs based on monoclonal antibodies (mAbs) like the Pastorex(TM) Crypto Plus or the Remel Cryptococcus Antigen Test Kit turned out to have an insufficient sensitivity to detect four out of 10 C. gattii infections, including one infection by a hybrid between C. gattii and C. neoformans. Reflecting the ongoing expansion of C. gattii in geographical zones outside of tropical and subtropical areas like Mediterranean countries, Vancouver Island (British Columbia, Canada) and the Pacific Northwest region (USA), these findings are alarming because of the risk of delayed diagnosis of infections caused by C. gattii. Therefore, the preliminary serological screening for cryptococcal antigen in the case of a suspected Cryptococcus infection should be performed by using an assay with a broad range specificity and sensitivity for C. neoformans and C. gattii, including their hybrids. © The Author 2015. Published by Oxford University Press on behalf of The International Society for Human and Animal Mycology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Antimicrobial, wound healing and antioxidant activity of Plagiochasma appendiculatum Lehm. et Lind.

PubMed

Singh, Meenakshi; Govindarajan, Raghavan; Nath, Virendra; Rawat, Ajay Kumar Singh; Mehrotra, Shanta

2006-08-11

Plagiochasma appendiculatum (Aytoniaceae) of the order Marchantiales is widely used in the form of paste ethnomedicinally by Gaddi tribe in Kangra valley for treating skin diseases. In this context, antimicrobical potential of Plagiochasma appendiculatum against a wide range of microorganisms was studied. To validate the ethnotherapeutic claims of the plant in skin diseases, wound healing activity was studied, besides antioxidant activity to understand the mechanism of wound healing activity. The plant (alchoholic and aqueous extract) showed significant antibacterial and antifungal activity against almost all the organisms: Micrococcus luteus, Bacillus subtilis, Bacillus cereus, Staphylococcus aureus, Streptococcus pneumoniae, Enterobacter aerogenes, Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, Pseudomonas aeruginosa, Salmonella typhimurium, and eight fungi Candida albicans and Cryptococcus albidus-dimorphic fungi, Trichophyton rubrum-dermatophyte fungi, Aspergillus niger, Aspergillus flavus, Aspergillus spinulosus, Aspergillus terreus and Aspergillus nidulans-systemic fungi, with especially good activity against the dermatophyte (Trichophyton rubrum) and some infectious bacteria (Escherichia coli, Proteus mirabilis and Salmonella typhimurium) with an MIC of 2.5 microg/disc. The results show that Plagiochasma appendiculatum extract has potent wound healing capacity as evident from the wound contraction and increased tensile strength. The results also indicated that Plagiochasma appendiculatum extract possesses potent antioxidant activity by inhibiting lipid peroxidation and increase in the superoxide dismutase (SOD) and Catalase activity.

Central Role of the Trehalose Biosynthesis Pathway in the Pathogenesis of Human Fungal Infections: Opportunities and Challenges for Therapeutic Development.

PubMed

Thammahong, Arsa; Puttikamonkul, Srisombat; Perfect, John R; Brennan, Richard G; Cramer, Robert A

2017-06-01

Invasive fungal infections cause significant morbidity and mortality in part due to a limited antifungal drug arsenal. One therapeutic challenge faced by clinicians is the significant host toxicity associated with antifungal drugs. Another challenge is the fungistatic mechanism of action of some drugs. Consequently, the identification of fungus-specific drug targets essential for fitness in vivo remains a significant goal of medical mycology research. The trehalose biosynthetic pathway is found in a wide variety of organisms, including human-pathogenic fungi, but not in humans. Genes encoding proteins involved in trehalose biosynthesis are mechanistically linked to the metabolism, cell wall homeostasis, stress responses, and virulence of Candida albicans , Cryptococcus neoformans , and Aspergillus fumigatus . While there are a number of pathways for trehalose production across the tree of life, the TPS/TPP (trehalose-6-phosphate synthase/trehalose-6-phosphate phosphatase) pathway is the canonical pathway found in human-pathogenic fungi. Importantly, data suggest that proteins involved in trehalose biosynthesis play other critical roles in fungal metabolism and in vivo fitness that remain to be fully elucidated. By further defining the biology and functions of trehalose and its biosynthetic pathway components in pathogenic fungi, an opportunity exists to leverage this pathway as a potent antifungal drug target. The goal of this review is to cover the known roles of this important molecule and its associated biosynthesis-encoding genes in the human-pathogenic fungi studied to date and to employ these data to critically assess the opportunities and challenges facing development of this pathway as a therapeutic target. Copyright © 2017 American Society for Microbiology.

Stress signaling pathways for the pathogenicity of Cryptococcus.

PubMed

Bahn, Yong-Sun; Jung, Kwang-Woo

2013-12-01

Sensing, responding, and adapting to the surrounding environment are crucial for all living organisms to survive, proliferate, and differentiate in their biological niches. This ability is also essential for Cryptococcus neoformans and its sibling species Cryptococcus gattii, as these pathogens have saprobic and parasitic life cycles in natural and animal host environments. The ability of Cryptococcus to cause fatal meningoencephalitis is highly related to its capability to remodel and optimize its metabolic and physiological status according to external cues. These cues act through multiple stress signaling pathways through a panoply of signaling components, including receptors/sensors, small GTPases, secondary messengers, kinases, transcription factors, and other miscellaneous adaptors or regulators. In this minireview, we summarize and highlight the importance of several stress signaling pathways that influence the pathogenicity of Cryptococcus and discuss future challenges in these areas.

Stress Signaling Pathways for the Pathogenicity of Cryptococcus

PubMed Central

Jung, Kwang-Woo

2013-01-01

Sensing, responding, and adapting to the surrounding environment are crucial for all living organisms to survive, proliferate, and differentiate in their biological niches. This ability is also essential for Cryptococcus neoformans and its sibling species Cryptococcus gattii, as these pathogens have saprobic and parasitic life cycles in natural and animal host environments. The ability of Cryptococcus to cause fatal meningoencephalitis is highly related to its capability to remodel and optimize its metabolic and physiological status according to external cues. These cues act through multiple stress signaling pathways through a panoply of signaling components, including receptors/sensors, small GTPases, secondary messengers, kinases, transcription factors, and other miscellaneous adaptors or regulators. In this minireview, we summarize and highlight the importance of several stress signaling pathways that influence the pathogenicity of Cryptococcus and discuss future challenges in these areas. PMID:24078305

Evaluation of Novel Broad-Range Real-Time PCR Assay for Rapid Detection of Human Pathogenic Fungi in Various Clinical Specimens▿

PubMed Central

Vollmer, Tanja; Störmer, Melanie; Kleesiek, Knut; Dreier, Jens

2008-01-01

In the present study, a novel broad-range real-time PCR was developed for the rapid detection of human pathogenic fungi. The assay targets a part of the 28S large-subunit ribosomal RNA (rDNA) gene. We investigated its application for the most important human pathogenic fungal genera, including Aspergillus, Candida, Cryptococcus, Mucor, Penicillium, Pichia, Microsporum, Trichophyton, and Scopulariopsis. Species were identified in PCR-positive reactions by direct DNA sequencing. A noncompetitive internal control was applied to prevent false-negative results due to PCR inhibition. The minimum detection limit for the PCR was determined to be one 28S rDNA copy per PCR, and the 95% detection limit was calculated to 15 copies per PCR. To assess the clinical applicability of the PCR method, intensive-care patients with artificial respiration and patients with infective endocarditis were investigated. For this purpose, 76 tracheal secretion samples and 70 heart valve tissues were analyzed in parallel by real-time PCR and cultivation. No discrepancies in results were observed between PCR analysis and cultivation methods. Furthermore, the application of the PCR method was investigated for other clinical specimens, including cervical swabs, nail and horny skin scrapings, and serum, blood, and urine samples. The combination of a broad-range real-time PCR and direct sequencing facilitates rapid screening for fungal infection in various clinical specimens. PMID:18385440

Evaluation of novel broad-range real-time PCR assay for rapid detection of human pathogenic fungi in various clinical specimens.

PubMed

Vollmer, Tanja; Störmer, Melanie; Kleesiek, Knut; Dreier, Jens

2008-06-01

In the present study, a novel broad-range real-time PCR was developed for the rapid detection of human pathogenic fungi. The assay targets a part of the 28S large-subunit ribosomal RNA (rDNA) gene. We investigated its application for the most important human pathogenic fungal genera, including Aspergillus, Candida, Cryptococcus, Mucor, Penicillium, Pichia, Microsporum, Trichophyton, and Scopulariopsis. Species were identified in PCR-positive reactions by direct DNA sequencing. A noncompetitive internal control was applied to prevent false-negative results due to PCR inhibition. The minimum detection limit for the PCR was determined to be one 28S rDNA copy per PCR, and the 95% detection limit was calculated to 15 copies per PCR. To assess the clinical applicability of the PCR method, intensive-care patients with artificial respiration and patients with infective endocarditis were investigated. For this purpose, 76 tracheal secretion samples and 70 heart valve tissues were analyzed in parallel by real-time PCR and cultivation. No discrepancies in results were observed between PCR analysis and cultivation methods. Furthermore, the application of the PCR method was investigated for other clinical specimens, including cervical swabs, nail and horny skin scrapings, and serum, blood, and urine samples. The combination of a broad-range real-time PCR and direct sequencing facilitates rapid screening for fungal infection in various clinical specimens.

Application of an oligonucleotide microarray-based nano-amplification technique for the detection of fungal pathogens.

PubMed

Lu, Weiping; Gu, Dayong; Chen, Xingyun; Xiong, Renping; Liu, Ping; Yang, Nan; Zhou, Yuanguo

2010-10-01

The traditional techniques for diagnosis of invasive fungal infections in the clinical microbiology laboratory need improvement. These techniques are prone to delay results due to their time-consuming process, or result in misidentification of the fungus due to low sensitivity or low specificity. The aim of this study was to develop a method for the rapid detection and identification of fungal pathogens. The internal transcribed spacer two fragments of fungal ribosomal DNA were amplified using a polymerase chain reaction for all samples. Next, the products were hybridized with the probes immobilized on the surface of a microarray. These species-specific probes were designed to detect nine different clinical pathogenic fungi including Candida albicans, Candida tropocalis, Candida glabrata, Candida parapsilosis, Candida krusei, Candida lusitaniae, Candida guilliermondii, Candida keyfr, and Cryptococcus neoformans. The hybridizing signals were enhanced with gold nanoparticles and silver deposition, and detected using a flatbed scanner or visually. Fifty-nine strains of fungal pathogens, including standard and clinically isolated strains, were correctly identified by this method. The sensitivity of the assay for Candida albicans was 10 cells/mL. Ten cultures from clinical specimens and 12 clinical samples spiked with fungi were also identified correctly. This technique offers a reliable alternative to conventional methods for the detection and identification of fungal pathogens. It has higher efficiency, specificity and sensitivity compared with other methods commonly used in the clinical laboratory.

Pigment production on L-tryptophan medium by Cryptococcus gattii and Cryptococcus neoformans.

PubMed

Chaskes, Stuart; Cammer, Michael; Nieves, Edward; Casadevall, Arturo

2014-01-01

In recent years strains previously grouped within Cryptococcus neoformans have been divided into two species C. neoformans and C. gattii, with Cryptococcus neoformans comprising serotypes A, D, and AD and C. gattii comprising serotypes B and C. Cryptococcus neoformans have also been subdivided into two varieties C. neoformans var. grubii, serotype A, and C. neoformans var. neoformans, serotype D. We analyzed the growth and pigment production characteristics of 139 strains of Cryptococcus spp. in L-tryptophan containing media. Nearly all strains of Cryptococcus, including each variety and serotype tested produced a pink water-soluble pigment (molecular weight of 535.2 Da) from L-tryptophan. Consequently, the partial separation of the species was based on whether the pink pigment was secreted into the medium (extracellular) or retained as an intracellular pigment. On L-tryptophan medium C. neoformans var. grubii and serotype AD produced a pink extracellular pigment. In contrast, for C. gattii, the pink pigment was localized intracellularly and masked by heavy production of brown pigments. Pigment production by C. neoformans var. neoformans was variable with some strains producing the pink extracellular pigment and others retained the pink pigment intracellularly. The pink intracellular pigment produced by strains of C. neoformans var. neoformans was masked by production of brown pigments. Cryptococcus laccase mutants failed to produce pigments from L-tryptophan. This is the first report that the enzyme laccase is involved in tryptophan metabolism. Prior to this report Cryptococcus laccase produced melanin or melanin like-pigments from heterocyclic compounds that contained ortho or para diphenols, diaminobenzenes and aminophenol compounds. The pigments produced from L-tryptophan were not melanin.

Genomics and Transcriptomics Analyses of the Oil-Accumulating Basidiomycete Yeast Trichosporon oleaginosus: Insights into Substrate Utilization and Alternative Evolutionary Trajectories of Fungal Mating Systems

PubMed Central

Bracharz, Felix; Lorenzen, Jan; Kracht, Octavia N.; Chovatia, Mansi; Daum, Chris; Deshpande, Shweta; Lipzen, Anna; Nolan, Matt; Ohm, Robin A.; Grigoriev, Igor V.; Sun, Sheng; Heitman, Joseph

2015-01-01

ABSTRACT Microbial fermentation of agro-industrial waste holds great potential for reducing the environmental impact associated with the production of lipids for industrial purposes from plant biomass. However, the chemical complexity of many residues currently prevents efficient conversion into lipids, creating a high demand for strains with the ability to utilize all energy-rich components of agricultural residues. Here, we present results of genome and transcriptome analyses of Trichosporon oleaginosus. This oil-accumulating yeast is able to grow on a wide variety of substrates, including pentoses and N-acetylglucosamine, making it an interesting candidate for biotechnological applications. Transcriptomics shows specific changes in gene expression patterns under lipid-accumulating conditions. Furthermore, gene content and expression analyses indicate that T. oleaginosus is well-adapted for the utilization of chitin-rich biomass. We also focused on the T. oleaginosus mating type, because this species is a member of the Tremellomycetes, a group that has been intensively analyzed as a model for the evolution of sexual development, the best-studied member being Cryptococcus neoformans. The structure of the T. oleaginosus mating-type regions differs significantly from that of other Tremellomycetes and reveals a new evolutionary trajectory paradigm. Comparative analysis shows that recruitment of developmental genes to the ancestral tetrapolar mating-type loci occurred independently in the Trichosporon and Cryptococcus lineages, supporting the hypothesis of a trend toward larger mating-type regions in fungi. PMID:26199329

[In vitro activity of voriconazole against yeast and algae isolates according to new resistance pattern cut-off points].

PubMed

Pemán, J; Cantón, E; Calabuig, E; Bosch, M; Valentí, A; Viudes, A; Gobernado, M

2006-03-01

Voriconazole is a second-generation triazole derived from fluconazole but with greater potency and spectrum of activity, showing good in vitro activity against Candida, Cryptococcus and Aspergillus species, and other filamentous and dimorphic fungi. It can be administered orally or intravenously. It was initially approved in 2002 by the U.S. Food and Drug Administration as a treatment option for invasive aspergillosis and Fusarium and S. apiospermum infections showing resistance or intolerance to other antifungals; later on, it also received approval in the United States and Europe as a treatment option for esophageal candidiasis; candida infection in non-neutropenic patients; disseminated candidiasis of skin, abdomen, kidney and bladder; and injuries. Recently, the Clinical Laboratory Standard Institute established some provisional break points for voriconazole, classifying isolates with an MICor=4 mg/l as resistant. In line with these new data, we performed a systematic review of literature on in vitro activity of voriconazole against yeast and algae isolates, and compared it to that of fluconazole and itraconazole. The review included a total of 27,340 yeast isolates, 24,177 of Candida species, 2,726 of Cryptococcus species, 453 of other species, and 104 Prototheca. The yeast isolates resistant to voriconazole is approximately 1%, and 71% of fluconazole-resistant isolates are susceptible to voriconazole.

A Chitin Synthase and Its Regulator Protein Are Critical for Chitosan Production and Growth of the Fungal Pathogen Cryptococcus neoformans†

PubMed Central

Banks, Isaac R.; Specht, Charles A.; Donlin, Maureen J.; Gerik, Kimberly J.; Levitz, Stuart M.; Lodge, Jennifer K.

2005-01-01

Chitin is an essential component of the cell wall of many fungi. Chitin also can be enzymatically deacetylated to chitosan, a more flexible and soluble polymer. Cryptococcus neoformans is a fungal pathogen that causes cryptococcal meningoencephalitis, particularly in immunocompromised patients. In this work, we show that both chitin and chitosan are present in the cell wall of vegetatively growing C. neoformans yeast cells and that the levels of both rise dramatically as cells grow to higher density in liquid culture. C. neoformans has eight putative chitin synthases, and strains with any one chitin synthase deleted are viable at 30°C. In addition, C. neoformans genes encode three putative regulator proteins, which are homologs of Saccharomyces cerevisiae Skt5p. None of these three is essential for viability. However, one of the chitin synthases (Chs3) and one of the regulators (Csr2) are important for growth. Cells with deletions in either CHS3 or CSR2 have several shared phenotypes, including sensitivity to growth at 37°C. The similarity of their phenotypes also suggests that Csr2 specifically regulates chitin synthesis by Chs3. Lastly, both chs3Δ and the csr2Δ mutants are defective in chitosan production, predicting that Chs3-Csr2 complex with chitin deacetylases for conversion of chitin to chitosan. These data suggest that chitin synthesis could be an excellent antifungal target. PMID:16278457

A chitin synthase and its regulator protein are critical for chitosan production and growth of the fungal pathogen Cryptococcus neoformans.

PubMed

Banks, Isaac R; Specht, Charles A; Donlin, Maureen J; Gerik, Kimberly J; Levitz, Stuart M; Lodge, Jennifer K

2005-11-01

Chitin is an essential component of the cell wall of many fungi. Chitin also can be enzymatically deacetylated to chitosan, a more flexible and soluble polymer. Cryptococcus neoformans is a fungal pathogen that causes cryptococcal meningoencephalitis, particularly in immunocompromised patients. In this work, we show that both chitin and chitosan are present in the cell wall of vegetatively growing C. neoformans yeast cells and that the levels of both rise dramatically as cells grow to higher density in liquid culture. C. neoformans has eight putative chitin synthases, and strains with any one chitin synthase deleted are viable at 30 degrees C. In addition, C. neoformans genes encode three putative regulator proteins, which are homologs of Saccharomyces cerevisiae Skt5p. None of these three is essential for viability. However, one of the chitin synthases (Chs3) and one of the regulators (Csr2) are important for growth. Cells with deletions in either CHS3 or CSR2 have several shared phenotypes, including sensitivity to growth at 37 degrees C. The similarity of their phenotypes also suggests that Csr2 specifically regulates chitin synthesis by Chs3. Lastly, both chs3Delta and the csr2Delta mutants are defective in chitosan production, predicting that Chs3-Csr2 complex with chitin deacetylases for conversion of chitin to chitosan. These data suggest that chitin synthesis could be an excellent antifungal target.

Cryptococcus interactions with macrophages: evasion and manipulation of the phagosome by a fungal pathogen.

PubMed

Johnston, Simon A; May, Robin C

2013-03-01

Cryptococcus is a potentially fatal fungal pathogen and a leading cause of death in immunocompromised patients. As an opportunistic and facultative intracellular pathogen of humans, Cryptococcus exhibits a complex set of interactions with the host immune system in general, and macrophages in particular. Cryptococcus is resistant to phagocytosis but is also able to survive and proliferate within the mature phagolysosome. It can cause the lysis of host cells, can be transferred between macrophages or exit non-lytically via vomocytosis. Efficient phagocytosis is reliant on opsonization and Cryptococcus has a number of anti-phagocytic strategies including formation of titan cells and a thick polysaccharide capsule. Following uptake, phagosome maturation appears to occur normally, but the internalized pathogen is able to survive and replicate. Here we review the interactions and host manipulation processes that occur within cryptococcal-infected macrophages and highlight areas for future research. © 2012 Blackwell Publishing Ltd.

Advances in Cryptococcus genomics: insights into the evolution of pathogenesis.

PubMed

Cuomo, Christina A; Rhodes, Johanna; Desjardins, Christopher A

2018-01-01

Cryptococcus species are the causative agents of cryptococcal meningitis, a significant source of mortality in immunocompromised individuals. Initial work on the molecular epidemiology of this fungal pathogen utilized genotyping approaches to describe the genetic diversity and biogeography of two species, Cryptococcus neoformans and Cryptococcus gattii. Whole genome sequencing of representatives of both species resulted in reference assemblies enabling a wide array of downstream studies and genomic resources. With the increasing availability of whole genome sequencing, both species have now had hundreds of individual isolates sequenced, providing fine-scale insight into the evolution and diversification of Cryptococcus and allowing for the first genome-wide association studies to identify genetic variants associated with human virulence. Sequencing has also begun to examine the microevolution of isolates during prolonged infection and to identify variants specific to outbreak lineages, highlighting the potential role of hyper-mutation in evolving within short time scales. We can anticipate that further advances in sequencing technology and sequencing microbial genomes at scale, including metagenomics approaches, will continue to refine our view of how the evolution of Cryptococcus drives its success as a pathogen.

Bioconversion of Xylan to triglycerides by oil-rich yeasts. [Cryptococcus albidus; Cryptococcus terricoluus; Trichosporon

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fall, R.; Phelps, P.; Spindler, D.

A series of lipid-accumulating yeasts was examined for their potential to saccharify xylan and accumulate triglyceride. Of the genera tested, including Candida, Cryptococcus, Lipomyces, Rhodosporidium, Rhodotorula, and Trichosporon, only Crytococcus and Trichosporon isolates saccharified xylan. All of the strains could assimilate xylose and accumuate triglyceride under nitrogen-limiting conditions. Strains of Cryptococcus albidus were found to be especially useful for a one-step saccharification of xylan coupled to triglyceride synthesis. Crytococcus terricolus, a strain constitutive for lipid accumulation, lacked extracellular xylanase, but did assimilate xylose and xylobiose and was able to continuously convert xylan to triglyceride if the culture medium was supplementedmore » with xylanase. 22 references.« less

Incidental Finding of Cryptococcus on Prostate Biopsy for Prostate Adenocarcinoma Following Cardiac Transplant: Case Report and Review of the Literature.

PubMed

Shah, Sujal I; Bui, Hai; Velasco, Nelson; Rungta, Shilpa

2017-11-06

BACKGROUND Cryptococcus is the third most common invasive fungal organism in immunocompromised patients, including transplant patients, and usually involves the central nervous system and lungs, with a median time to infection of 25 months. We report a case of Cryptococcus of the prostate gland, found as an incidental finding on prostate biopsy for prostate adenocarcinoma, four months following cardiac transplantation. CASE REPORT A 62-year-old male African-American who had a cardiac transplant four months previously, underwent a six-core prostate biopsy for a two-year history of increasing prostate-specific antigen (PSA) levels, and a recent history of non-specific urinary tract symptoms. A prostatic adenocarcinoma, Gleason grade 4+4=8, was diagnosed on histopathology, and 'foamy' cells were seen in the biopsies. Histochemical stains, including Grocott methenamine silver (GMS), and periodic acid-Schiff (PAS) showed abundant round and oval 5-7 µm diameter fungal elements; mucicarmine highlighted the fungal polysaccharide capsule, diagnostic for Cryptococcus. Cryptococcal antigen detection was made by the latex agglutination test and cultures. We reviewed the literature and found 70 published cases (from 1946-2008) of Cryptococcus of the prostate gland, with only one previous case presenting five years following cardiac transplantation. CONCLUSIONS Fungal infections of the prostate are rare, and occur mainly in immunocompromised patients. We present a unique case of prostatic Cryptococcus found incidentally at four months following cardiac transplantation. This case report highlights the need to consider atypical fungal infection as a differential diagnosis for prostatitis in immunosuppressed patients, including transplant patients.

Antimicrobial Activity of Extracts of the Oyster Culinary Medicinal Mushroom Pleurotus ostreatus (Higher Basidiomycetes) and Identification of a New Antimicrobial Compound.

PubMed

Younis, Ahmed M; Wu, Fang-Sheng; El Shikh, Hussien H

2015-01-01

Pleurotus ostreatus is an edible mushroom that also has high medicinal values. In this study, P. ostreatus was tested for its ability to inhibit the growth of fungi and bacteria. The freeze-dried fruiting body, broth from submerged culture, and mycelial biomass of P. ostreatus were extracted using alcohols and water as solvents. The extracts were then tested for their antimicrobial activity against the growth of fungi and bacteria. It was observed that the water extract from fruiting bodies had the strongest effect in inhibiting the growth of most fungi. The most sensitive test microfungi to the inhibition were Candida albicans, Cryptococcus humicola, and Trichosporon cutaneum, and the most sensitive test bacteria were Staphylococcus aureus followed by Escherichia coli. Water extracts from culture broth or mycelial biomass were moderately inhibitive to the growth of fungi and bacteria. The alcohol-based solvents from all samples had much less antimicrobial activity against most test microorganisms. An antimicrobial compound was purified from the water extracts of fruiting bodies with Sephadex G 100 column chromatography and characterized by infrared absorption spectrum (IR), nuclear magnetic resonance (NMR), and mass spectroscopic analysis. We have identified this compound to be 3-(2-aminopheny1thio)-3-hydroxypropanoic acid. This purified compound had a minimum inhibitory concentration of 30 µg/mL and 20 µg/mL against the growth of fungi and bacteria, respectively.

Screening of antifungal agents using ethanol precipitation and bioautography of medicinal and food plants.

PubMed

Schmourlo, Gracilene; Mendonça-Filho, Ricardo R; Alviano, Celuta Sales; Costa, Sônia S

2005-01-15

In the search for bioactive compounds, bioautography and ethanol precipitation of macromolecules (proteins, polysaccharides, etc.) of plant aqueous extracts were associated in an antifungal screening. Thus, the supernatants, precipitates (obtained by ethanol precipitation) and aqueous extracts were investigated of medicinal and fruit bearing plants used against skin diseases by the Brazilian population. The agar diffusion and broth dilution methods were used to assess the activity against three fungi: Candida albicans, Trichophyton rubrum and Cryptococcus neoformans. The results, evaluated by the diameter of the inhibition zone of fungal growth, indicate that six plant species, among the 16 investigated, showed significant antifungal activity. The minimal inhibitory concentration (MIC) was determined on plant extracts that showed high efficacy against the tested microorganisms. The most susceptible yeast was Trichophyton rubrum and the best antifungal activity was shown by Xanthosoma sagittifolium supernatant. The bioautography was performed only for the aqueous extracts and supernatants of those plants that showed antifungal activity against Candida albicans and Cryptococcus neoformans, using n-butanol/acetic acid/water (BAW) 8:1:1 to develop silica gel TLC plates. Clear inhibition zones were observed for aqueous extracts of Schinus molle (R(f) 0.89) and Schinus terebinthifolius (R(f) 0.80) against Candida albicans, as for supernatant of Anacardium occidentale (R(f) 0.31) against Cryptococcus neoformans. The separation of macromolecules from metabolites, as in the case of Anacardium occidentale, Solanum sp. and Xanthosoma sagittifolium, enhances antifungal activity. In other cases, the antifungal activity is destroyed, as observed for Momordica charantia, Schinus molle and Schinus terebinthifolius.

Isavuconazole Treatment of Cryptococcosis and Dimorphic Mycoses.

PubMed

Thompson, George R; Rendon, Adrian; Ribeiro Dos Santos, Rodrigo; Queiroz-Telles, Flavio; Ostrosky-Zeichner, Luis; Azie, Nkechi; Maher, Rochelle; Lee, Misun; Kovanda, Laura; Engelhardt, Marc; Vazquez, Jose A; Cornely, Oliver A; Perfect, John R

2016-08-01

Invasive fungal diseases (IFD) caused by Cryptococcus and dimorphic fungi are associated with significant morbidity and mortality. Isavuconazole (ISAV) is a novel, broad-spectrum, triazole antifungal agent (IV and by mouth [PO]) developed for the treatment of IFD. It displays potent activity in vitro against these pathogens and in this report we examine outcomes of patients with cryptococcosis or dimorphic fungal infections treated with ISAV. The VITAL study was an open-label nonrandomized phase 3 trial conducted to evaluate the efficacy and safety of ISAV treatment in management of rare IFD. Patients received ISAV 200 mg 3 times daily for 2 days followed by 200 mg once-daily (IV or PO). Proven IFD and overall response at end of treatment (EOT) were determined by an independent, data-review committee. Mortality and safety were also assessed. Thirty-eight patients received ISAV for IFD caused by Cryptococcus spp. (n = 9), Paracoccidioides spp. (n = 10), Coccidioides spp. (n = 9), Histoplasma spp. (n = 7) and Blastomyces spp. (n = 3). The median length of therapy was 180 days (range 2-331 days). At EOT 24/38 (63%) patients exhibited a successful overall response. Furthermore, 8 of 38 (21%) had stable IFD at the end of therapy without progression of disease, and 6 (16%) patients had progressive IFD despite this antifungal therapy. Thirty-three (87%) patients experienced adverse events. ISAV was well tolerated and demonstrated clinical activity against these endemic fungi with a safety profile similar to that observed in larger studies, validating its broad-spectrum in vitro activity and suggesting it may be a valuable alternative to currently available agents. NCT00634049. © The Author 2016. Published by Oxford University Press for the Infectious Diseases Society of America.

Rapid direct identification of Cryptococcus neoformans from pigeon droppings by nested PCR using CNLAC1 gene.

PubMed

Chae, H S; Park, G N; Kim, S H; Jo, H J; Kim, J T; Jeoung, H Y; An, D J; Kim, N H; Shin, B W; Kang, Y I; Chang, K S

2012-08-01

Isolation and identification of Cryptococcus neoformans and pathogenic yeast-like fungi from pigeon droppings has been taken for a long time and requires various nutrients for its growth. In this study, we attempted to establish a rapid direct identification method of Cr. neoformans from pigeon dropping samples by nested-PCR using internal transcribed spacer (ITS) CAP64 and CNLAC1 genes, polysaccharide capsule gene and laccase-associated gene to produce melanin pigment, respectively, which are common genes of yeasts. The ITS and CAP64 genes were amplified in all pathogenic yeasts, but CNLAC1 was amplified only in Cr. neoformans. The ITS gene was useful for yeast genotyping depending on nucleotide sequence. Homology of CAP64 genes among the yeasts were very high. The specificity of PCR using CNLAC1 was demonstrated in Cr. neoformans environmental strains but not in other yeast-like fungi. The CNLAC1 gene was detected in 5 serotypes of Cr. neoformans. The nested-PCR amplified up to 10(-11) μg of the genomic DNA and showed high sensitivity. All pigeon droppings among 31 Cr. neoformans-positive samples were positive and all pigeon droppings among 348 Cr. neoformans-negative samples were negative by the direct nested-PCR. In addition, after primary enrichment of pigeon droppings in Sabouraud dextrose broth, all Cr. neoformans-negative samples were negative by the nested-PCR, which showed high specificity. The nested-PCR showed high sensitivity without culture of pigeon droppings. Nested-PCR using CNLAC1 provides a rapid and reliable molecular diagnostic method to overcome weak points such as long culture time of many conventional methods.

Transitions in Sexuality: Recapitulation of an Ancestral Tri- and Tetrapolar Mating System in Cryptococcus neoformans▿ †

PubMed Central

Hsueh, Yen-Ping; Fraser, James A.; Heitman, Joseph

2008-01-01

Sex is orchestrated by the mating-type locus (MAT) in fungi and by sex chromosomes in plants and animals. In fungi, two patterns of sexuality occur: bipolar with a single, typically biallelic sex determinant that promotes inbreeding, and tetrapolar with two unlinked, often multiallelic sex determinants that restrict inbreeding. Multiallelism in either bipolar or tetrapolar mating systems promotes outcrossing. Cryptococcus neoformans is a pathogenic bipolar yeast with two unusually large MAT alleles (a/α) spanning >100 kb, ∼100-fold larger than many other fungal MAT loci. Based on comparative genomic analysis, this unusual MAT locus is hypothesized to have evolved from an ancestral tetrapolar system. In this model, the unlinked homeodomain (HD) transcription factor and pheromone/receptor tetrapolar loci acquired additional sex-related genes and then fused via chromosomal translocation, forming an intermediate transitional mating system (which we term tripolar), which then underwent recombination and gene conversion to fashion the extant bipolar MAT alleles. To experimentally validate this model, C. neoformans was engineered to have a tetrapolar mating system by relocating the MAT SXI1α and SXI2a HD genes to an unlinked genomic locale. Genetic and molecular analyses revealed that this modified organism could complete a tetrapolar sexual cycle. Analysis of progeny generated from bipolar, tripolar, and tetrapolar crosses provides direct experimental evidence that the tripolar state confers decreased fertility and therefore may represent an unstable evolutionary intermediate. These findings illustrate how transitions between outcrossing and inbreeding preference occur by involving sex determinant linkage and collapse from multiallelic to biallelic sex determination, providing insights into both fungal sex evolution and early steps in sex chromosome evolution. PMID:18723606

A Cationic Polymer That Shows High Antifungal Activity against Diverse Human Pathogens.

PubMed

Rank, Leslie A; Walsh, Naomi M; Liu, Runhui; Lim, Fang Yun; Bok, Jin Woo; Huang, Mingwei; Keller, Nancy P; Gellman, Samuel H; Hull, Christina M

2017-10-01

Invasive fungal diseases are generally difficult to treat and often fatal. The therapeutic agents available to treat fungi are limited, and there is a critical need for new agents to combat these deadly infections. Antifungal compound development has been hindered by the challenge of creating agents that are highly active against fungal pathogens but not toxic to the host. Host defense peptides (HDPs) are produced by eukaryotes as a component of the innate immune response to pathogens and have served as inspiration for the development of many new antibacterial compounds. HDP mimics, however, have largely failed to exhibit potent and selective antifungal activity. Here, we present an HDP-like nylon-3 copolymer that is effective against diverse fungi while displaying only mild to moderate toxicity toward mammalian cells. This polymer is active on its own and in synergy with existing antifungal drugs against multiple species of Candida and Cryptococcus , reaching levels of efficacy comparable to those of the clinical agents amphotericin B and fluconazole in some cases. In addition, the polymer acts synergistically with azoles against different species of Aspergillus , including some azole-resistant strains. These findings indicate that nylon-3 polymers are a promising lead for development of new antifungal therapeutic strategies. Copyright © 2017 American Society for Microbiology.

Proteomic Analysis of Pathogenic Fungi Reveals Highly Expressed Conserved Cell Wall Proteins

PubMed Central

Champer, Jackson; Ito, James I.; Clemons, Karl V.; Stevens, David A.; Kalkum, Markus

2016-01-01

We are presenting a quantitative proteomics tally of the most commonly expressed conserved fungal proteins of the cytosol, the cell wall, and the secretome. It was our goal to identify fungi-typical proteins that do not share significant homology with human proteins. Such fungal proteins are of interest to the development of vaccines or drug targets. Protein samples were derived from 13 fungal species, cultured in rich or in minimal media; these included clinical isolates of Aspergillus, Candida, Mucor, Cryptococcus, and Coccidioides species. Proteomes were analyzed by quantitative MSE (Mass Spectrometry—Elevated Collision Energy). Several thousand proteins were identified and quantified in total across all fractions and culture conditions. The 42 most abundant proteins identified in fungal cell walls or supernatants shared no to very little homology with human proteins. In contrast, all but five of the 50 most abundant cytosolic proteins had human homologs with sequence identity averaging 59%. Proteomic comparisons of the secreted or surface localized fungal proteins highlighted conserved homologs of the Aspergillus fumigatus proteins 1,3-β-glucanosyltransferases (Bgt1, Gel1-4), Crf1, Ecm33, EglC, and others. The fact that Crf1 and Gel1 were previously shown to be promising vaccine candidates, underlines the value of the proteomics data presented here. PMID:26878023

Iron and copper as virulence modulators in human fungal pathogens.

PubMed

Ding, Chen; Festa, Richard A; Sun, Tian-Shu; Wang, Zhan-You

2014-07-01

Fungal pathogens have evolved sophisticated machinery to precisely balance the fine line between acquiring essential metals and defending against metal toxicity. Iron and copper are essential metals for many processes in both fungal pathogens and their mammalian hosts, but reduce viability when present in excess. However, during infection, the host uses these two metals differently. Fe has a long-standing history of influencing virulence in pathogenic fungi, mostly in regards to Fe acquisition. Numerous studies demonstrate the requirement of the Fe acquisition pathway of Candida, Cryptococcus and Aspergillus for successful systemic infection. Fe is not free in the host, but is associated with Fe-binding proteins, leading fungi to develop mechanisms to interact with and to acquire Fe from these Fe-bound proteins. Cu is also essential for cell growth and development. Essential Cu-binding proteins include Fe transporters, superoxide dismutase (SOD) and cytochrome c oxidase. Although Cu acquisition plays critical roles in fungal survival in the host, recent work has revealed that Cu detoxification is extremely important. Here, we review fungal responses to altered metal conditions presented by the host, contrast the roles of Fe and Cu during infection, and outline the critical roles of fungal metal homeostasis machinery at the host-pathogen axis. © 2014 John Wiley & Sons Ltd.

Pigment Production on L-Tryptophan Medium by Cryptococcus gattii and Cryptococcus neoformans

PubMed Central

Chaskes, Stuart; Cammer, Michael; Nieves, Edward; Casadevall, Arturo

2014-01-01

In recent years strains previously grouped within Cryptococcus neoformans have been divided into two species C. neoformans and C. gattii, with Cryptococcus neoformans comprising serotypes A, D, and AD and C. gattii comprising serotypes B and C. Cryptococcus neoformans have also been subdivided into two varieties C. neoformans var. grubii, serotype A, and C. neoformans var. neoformans, serotype D. We analyzed the growth and pigment production characteristics of 139 strains of Cryptococcus spp. in L-tryptophan containing media. Nearly all strains of Cryptococcus, including each variety and serotype tested produced a pink water-soluble pigment (molecular weight of 535.2 Da) from L-tryptophan. Consequently, the partial separation of the species was based on whether the pink pigment was secreted into the medium (extracellular) or retained as an intracellular pigment. On L-tryptophan medium C. neoformans var. grubii and serotype AD produced a pink extracellular pigment. In contrast, for C. gattii, the pink pigment was localized intracellularly and masked by heavy production of brown pigments. Pigment production by C. neoformans var. neoformans was variable with some strains producing the pink extracellular pigment and others retained the pink pigment intracellularly. The pink intracellular pigment produced by strains of C. neoformans var. neoformans was masked by production of brown pigments. Cryptococcus laccase mutants failed to produce pigments from L-tryptophan. This is the first report that the enzyme laccase is involved in tryptophan metabolism. Prior to this report Cryptococcus laccase produced melanin or melanin like-pigments from heterocyclic compounds that contained ortho or para diphenols, diaminobenzenes and aminophenol compounds. The pigments produced from L-tryptophan were not melanin. PMID:24736553

Unisexual and Heterosexual Meiotic Reproduction Generate Aneuploidy and Phenotypic Diversity De Novo in the Yeast Cryptococcus neoformans

PubMed Central

Li, Wenjun; Floyd-Averette, Anna; Mieczkowski, Piotr; Dietrich, Fred S.; Heitman, Joseph

2013-01-01

Aneuploidy is known to be deleterious and underlies several common human diseases, including cancer and genetic disorders such as trisomy 21 in Down's syndrome. In contrast, aneuploidy can also be advantageous and in fungi confers antifungal drug resistance and enables rapid adaptive evolution. We report here that sexual reproduction generates phenotypic and genotypic diversity in the human pathogenic yeast Cryptococcus neoformans, which is globally distributed and commonly infects individuals with compromised immunity, such as HIV/AIDS patients, causing life-threatening meningoencephalitis. C. neoformans has a defined a-α opposite sexual cycle; however, >99% of isolates are of the α mating type. Interestingly, α cells can undergo α-α unisexual reproduction, even involving genotypically identical cells. A central question is: Why would cells mate with themselves given that sex is costly and typically serves to admix preexisting genetic diversity from genetically divergent parents? In this study, we demonstrate that α-α unisexual reproduction frequently generates phenotypic diversity, and the majority of these variant progeny are aneuploid. Aneuploidy is responsible for the observed phenotypic changes, as chromosome loss restoring euploidy results in a wild-type phenotype. Other genetic changes, including diploidization, chromosome length polymorphisms, SNPs, and indels, were also generated. Phenotypic/genotypic changes were not observed following asexual mitotic reproduction. Aneuploidy was also detected in progeny from a-α opposite-sex congenic mating; thus, both homothallic and heterothallic sexual reproduction can generate phenotypic diversity de novo. Our study suggests that the ability to undergo unisexual reproduction may be an evolutionary strategy for eukaryotic microbial pathogens, enabling de novo genotypic and phenotypic plasticity and facilitating rapid adaptation to novel environments. PMID:24058295

Comparative typing analyses of clinical and environmental strains of the Cryptococcus neoformans/Cryptococcus gattii species complex from Ivory Coast.

PubMed

Kassi, Fulgence K; Bellet, Virginie; Drakulovski, Pascal; Krasteva, Donika; Roger, Frédéric; Valérie, Bedia-Tanoh A; Aboubakar, Touré; Doumbia, Adama; Kouakou, Gisèle A; Delaporte, Eric; Reynes, Jacques; Yavo, William; Menan, Hervé I E; Bertout, Sebastien

2018-01-01

The aim of this study was to assess the biotope of the Cryptococcus neoformans/Cryptococcus gattii species complex from Ivory Coast, and clarify the possible epidemiological relationship between environmental and clinical strains. Samples from Eucalyptus camaldulensis (n=136), Mangifera indica (n=13) and pigeon droppings (n=518) were collected from different sites close to the living environment of Ivorian HIV patients with cryptococcosis (n=10, 50 clinical strains). Clinical and environmental strains were characterized by molecular serotyping and genotyping [RFLP analysis of the URA5 gene, (GACA)4, (GTG)5 and M13 PCR fingerprinting] and compared.Results/Key findings. Environmental strains were recovered only from the pigeon droppings. In vitro susceptibility profiles showed that all strains were susceptible to fluconazole, flucytosine and amphotericin B. All environmental strains consisted of C. neoformans (A, AFLP1/VNI), whereas clinical strains included C. neoformans (A, AFLP1/VNI), C. neoformans x Cryptococcus deneoformans hybrids (AD, AFLP3/VNIII) and Cryptococcus deuterogattii (B, AFLP6/VGII). Two patients were co-infected with both C. neoformans and C. neoformans x C. deneoformans hybrids. We noticed a low genetic diversity among the environmental samples compared to the high diversity of the clinical samples. Some clinical strains were genetically more similar to environmental strains than to other clinical strains, including those from the same patient. These results provide new information on the ecology and epidemiology of the C. neoformans/C. gattii species complex in Ivory Coast.

Influence of long-term low levels of ozone on the leaf surface mycoflora of pinto bean plants

DOE Office of Scientific and Technical Information (OSTI.GOV)

Manning, W.J.; Papia, P.M.

Pinto bean plants (Phaseols vulgaris strain 111) were grown for 4, 7, 14, 21, or 28 days in greenhouses containing ambient air charcoal-filtered air or ozone at 6 pphm for 8 hr/day. Ozone was produced with a Welbach generator and monitored with Mast meters. The upper and lower surfaces of the first set of simple true leaves were used to make leaf prints on acidified potato-dextrose agar plates (PDA) at each sampling period. Discs cut from these leaves were washed 10 times in sterile water and plated on PDA. Results with leaf prints showed that species of 25 genera ofmore » fungi were present in recognizable successions on all leaves. The number of fungi per cm/sup 2/ leaf tissue increased with leaf age for all leaves, with the greatest number occurring on 28-day-old leaves with accumulated ozone flecks. Differences between leaves by sources was more quantitative than qualitative, with the exception of Aspergillus niger, which was common only on the leaves of plants grown in ambient air. Botrytis cincrea was commonly found on plates printed with leaves that had ozone fleck. Isolates of Candida, Cryptococcus, and Penicillium were the most abundant fungi on all leaves. Similar results were obtained with plated washed leaf discs except that the number of fungi genera present was reduced from 25 to 11.« less

Broad spectrum antibacterial and antifungal polymeric paint materials: synthesis, structure-activity relationship, and membrane-active mode of action.

PubMed

Hoque, Jiaul; Akkapeddi, Padma; Yadav, Vikas; Manjunath, Goutham B; Uppu, Divakara S S M; Konai, Mohini M; Yarlagadda, Venkateswarlu; Sanyal, Kaustuv; Haldar, Jayanta

2015-01-28

Microbial attachment and subsequent colonization onto surfaces lead to the spread of deadly community-acquired and hospital-acquired (nosocomial) infections. Noncovalent immobilization of water insoluble and organo-soluble cationic polymers onto a surface is a facile approach to prevent microbial contamination. In the present study, we described the synthesis of water insoluble and organo-soluble polymeric materials and demonstrated their structure-activity relationship against various human pathogenic bacteria including drug-resistant strains such as methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant enterococci (VRE), and beta lactam-resistant Klebsiella pneumoniae as well as pathogenic fungi such as Candida spp. and Cryptococcus spp. The polymer coated surfaces completely inactivated both bacteria and fungi upon contact (5 log reduction with respect to control). Linear polymers were more active and found to have a higher killing rate than the branched polymers. The polymer coated surfaces also exhibited significant activity in various complex mammalian fluids such as serum, plasma, and blood and showed negligible hemolysis at an amount much higher than minimum inhibitory amounts (MIAs). These polymers were found to have excellent compatibility with other medically relevant polymers (polylactic acid, PLA) and commercial paint. The cationic hydrophobic polymer coatings disrupted the lipid membrane of both bacteria and fungi and thus showed a membrane-active mode of action. Further, bacteria did not develop resistance against these membrane-active polymers in sharp contrast to conventional antibiotics and lipopeptides, thus the polymers hold great promise to be used as coating materials for developing permanent antimicrobial paint.

KB425796-A, a novel antifungal antibiotic produced by Paenibacillus sp. 530603.

PubMed

Kai, Hirohito; Yamashita, Midori; Takase, Shigehiro; Hashimoto, Michizane; Muramatsu, Hideyuki; Nakamura, Ikuko; Yoshikawa, Koji; Ezaki, Masami; Nitta, Kumiko; Watanabe, Masato; Inamura, Noriaki; Fujie, Akihiko

2013-08-01

The novel antifungal macrocyclic lipopeptidolactone, KB425796-A (1), was isolated from the fermentation broth of bacterial strain 530603, which was identified as a new Paenibacillus species based on morphological and physiological characteristics, and 16S rRNA sequences. KB425796-A (1) was isolated as white powder by solvent extraction, HP-20 and ODS-B column chromatography, and lyophilization, and was determined to have the molecular formula C79H115N19O18. KB425796-A (1) showed antifungal activities against Aspergillus fumigatus and the micafungin-resistant infectious fungi Trichosporon asahii, Rhizopus oryzae, Pseudallescheria boydii and Cryptococcus neoformans.

Antimicrobial and antiviral activities of polyphenolics from Cocos nucifera Linn. (Palmae) husk fiber extract.

PubMed

Esquenazi, Daniele; Wigg, Marcia D; Miranda, Mônica M F S; Rodrigues, Hugo M; Tostes, João B F; Rozental, Sonia; da Silva, Antonio J R; Alviano, Celuta S

2002-12-01

The decoction of Cocos nucifera L. husk fiber has been used in northeastern Brazil traditional medicine for treatment of diarrhea and arthritis. Water extract obtained from coconut husk fiber and fractions from adsorption chromatography revealed antimicrobial activity against Staphylococcus aureus. The crude extract and one of the fractions rich in catechin also showed inhibitory activity against acyclovir-resistant herpes simplex virus type 1 (HSV-1-ACVr). All fractions were inactive against the fungi Candida albicans, Fonsecaea pedrosoi and Cryptococcus neoformans. Catechin and epicatechin together with condensed tannins (B-type procyanidins) were demonstrated to be the components of the water extract.

Fungal associations in the build-up and decline of Cryptococcus fagisuga populations

Treesearch

David Lonsdale

1983-01-01

The fungal flora of Cryptococcus fagisuga colonies on Fagus sylvatica bark included the entomogenous species Verticillium lecanii wherever infestation was or had been very heavy. This fungus seemed to accelerate insect mortality in vitro. Cladosporium cladosporioides was present at all stages...

Prevalence of the genus Cladosporium on the integument of leaf-cutting ants characterized by 454 pyrosequencing.

PubMed

Duarte, A P M; Ferro, M; Rodrigues, A; Bacci, M; Nagamoto, N S; Forti, L C; Pagnocca, F C

2016-09-01

The relationship of attine ants with their mutualistic fungus and other microorganisms has been studied during the last two centuries. However, previous studies about the diversity of fungi in the ants' microenvironment are based mostly on culture-dependent approaches, lacking a broad characterization of the fungal ant-associated community. Here, we analysed the fungal diversity found on the integument of Atta capiguara and Atta laevigata alate ants using 454 pyrosequencing. We obtained 35,453 ITS reads grouped into 99 molecular operational taxonomic units (MOTUs). Data analysis revealed that A. capiguara drones had the highest diversity of MOTUs. Besides the occurrence of several uncultured fungi, the mycobiota analysis revealed that the most abundant taxa were the Cladosporium-complex, Cryptococcus laurentii and Epicoccum sp. Taxa in the genus Cladosporium were predominant in all samples, comprising 67.9 % of all reads. The remarkable presence of the genus Cladosporium on the integument of leaf-cutting ants alates from distinct ant species suggests that this fungus is favored in this microenvironment.

MALDI-TOF MS for the identification of veterinary non-C. neoformans-C. gattii Cryptococcus spp. isolates from Italy.

PubMed

Danesi, Patrizia; Drigo, Ilenia; Iatta, Roberta; Firacative, Carolina; Capelli, Gioia; Cafarchia, Claudia; Meyer, Wieland

2014-08-01

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) offers an effective alternative to phenotypic and molecular methods for the rapid identification of microorganisms. Our aim in this study was to create an in-house library for a set of strains of nine uncommonly reported human and animal cryptococcal species, including Cryptococcus adeliensis, C. albidosimilis, C. albidus, C. aureus, C. carnescens, C. laurentii, C. magnus, C. victoriae and C. uniguttulatus, and to use this library to make timely and correct identifications using MALDI-TOF MS for use in routine laboratory diagnostics. Protein extracts obtained via the formic acid extraction method of 62 veterinary non-C. neoformans-C. gattii cryptococcal isolates were studied. The obtained mass spectra correctly grouped all 62 studied isolates according to species identification previously obtained by internal transcribe spacer sequence analysis. The in-house database was than exported and successfully uploaded to the Microflex LT (Maldi Biotyper; Bruker Daltonics) instrument at a different diagnostic laboratory in Italy. Scores >2.7 obtained from isolates reanalyzed in the latter laboratory supported the high reproducibility of the method. The possibility of creating and transferring an in-house library adds to the usefulness MALDI-TOF MS an important tool for the rapid and inexpensive identification of pathogenic and saprophytic fungi as required for differential diagnosis of human and animal mycoses. © The Author 2014. Published by Oxford University Press on behalf of The International Society for Human and Animal Mycology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Cryptococcus neoformans var. grubii: Separate Varietal Status for Cryptococcus neoformans Serotype A Isolates

PubMed Central

Franzot, Sarah P.; Salkin, Ira F.; Casadevall, Arturo

1999-01-01

Cryptococcus neoformans var. neoformans presently includes isolates which have been determined by the immunologic reactivity of their capsular polysaccharides to be serotype A and those which have been determined to be serotype D. However, recent analyses of the URA5 sequences and DNA fingerprinting patterns suggest significant genetic differences between the two serotypes. Therefore, we propose to recognize these genotypic distinctions, as well as previously reported phenotypic differences, by restricting C. neoformans var. neoformans to isolates which are serotype D and describing a new variety, C. neoformans var. grubii, for serotype A isolates. PMID:9986871

Refractory and/or Relapsing Cryptococcosis Associated with Acquired Immune Deficiency Syndrome: Clinical Features, Genotype, and Virulence Factors of Cryptococcus spp. Isolates.

PubMed

Nascimento, Erika; Vitali, Lucia H; Tonani, Ludmilla; Kress, Marcia R Von Zeska; Takayanagui, Osvaldo M; Martinez, Roberto

2016-05-04

Refractory and relapsing crytocococcosis in acquired immune deficiency syndrome (AIDS) patients have a poor prognosis. The risk factors for this complicated infection course were evaluated by comparing refractory and/or relapsing cryptococcosis in human immunodeficiency virus-coinfected patients (cohort 1) with another group of AIDS patients who adequately responded to antifungals (cohort 2). Except for one isolate of Cryptococcus gattii from a cohort 2 case, all other isolates were identified as Cryptococcus neoformans var. grubii, sex type α, genotype VNI, including Cryptococcus reisolated from the relapse or in the refractory state. No differences were observed with respect to Cryptococcus capsule size and in the melanin and phospholipase production. The cohort 1 patients presented higher prevalence of cryptococcemia, cerebral dissemination, chronic liver disease, and leucopenia, and have increased death rate. Apparently, the refractory and/or relapsing cryptococcosis in the AIDS patients were more related to the host and the extent of the infection than to the fungal characteristics. © The American Society of Tropical Medicine and Hygiene.

Azole drugs are imported by facilitated diffusion in Candida albicans and other pathogenic fungi.

PubMed

Mansfield, Bryce E; Oltean, Hanna N; Oliver, Brian G; Hoot, Samantha J; Leyde, Sarah E; Hedstrom, Lizbeth; White, Theodore C

2010-09-30

Despite the wealth of knowledge regarding the mechanisms of action and the mechanisms of resistance to azole antifungals, very little is known about how the azoles are imported into pathogenic fungal cells. Here the in-vitro accumulation and import of Fluconazole (FLC) was examined in the pathogenic fungus, Candida albicans. In energized cells, FLC accumulation correlates inversely with expression of ATP-dependent efflux pumps. In de-energized cells, all strains accumulate FLC, suggesting that FLC import is not ATP-dependent. The kinetics of import in de-energized cells displays saturation kinetics with a K(m) of 0.64 μM and V(max) of 0.0056 pmol/min/10⁸ cells, demonstrating that FLC import proceeds via facilitated diffusion through a transporter rather than passive diffusion. Other azoles inhibit FLC import on a mole/mole basis, suggesting that all azoles utilize the same facilitated diffusion mechanism. An analysis of related compounds indicates that competition for azole import depends on an aromatic ring and an imidazole or triazole ring together in one molecule. Import of FLC by facilitated diffusion is observed in other fungi, including Cryptococcus neoformans, Saccharomyces cerevisiae, and Candida krusei, indicating that the mechanism of transport is conserved among fungal species. FLC import was shown to vary among Candida albicans resistant clinical isolates, suggesting that altered facilitated diffusion may be a previously uncharacterized mechanism of resistance to azole drugs.

Cytotoxic and Antifungal Constituents Isolated from the Metabolites of Endophytic Fungus DO14 from Dendrobium officinale.

PubMed

Wu, Ling-Shang; Jia, Min; Chen, Ling; Zhu, Bo; Dong, Hong-Xiu; Si, Jin-Ping; Peng, Wei; Han, Ting

2015-12-22

Two novel cytotoxic and antifungal constituents, (4S,6S)-6-[(1S,2R)-1, 2-dihydroxybutyl]-4-hydroxy-4-methoxytetrahydro-2H-pyran-2-one (1), (6S,2E)-6-hydroxy-3-methoxy-5-oxodec-2-enoic acid (2), together with three known compounds, LL-P880γ (3), LL-P880α (4), and Ergosta-5,7,22-trien-3b-ol (5) were isolated from the metabolites of endophytic fungi from Dendrobium officinale. The chemical structures were determined based on spectroscopic methods. All the isolated compounds 1-5 were evaluated by cytotoxicity and antifungal effects. Our present results indicated that compounds 1-4 showed notable anti-fungal activities (minimal inhibitory concentration (MIC) ≤ 50 μg/mL) for all the tested pathogens including Candida albicans, Cryptococcus neoformans, Trichophyton rubrum, Aspergillus fumigatus. In addition, compounds 1-4 possessed notable cytotoxcities against human cancer cell lines of HL-60 cells with the IC50 values of below 100 μM. Besides, compounds 1, 2, 4 and 5 showed strong cytotoxities on the LOVO cell line with the IC50 values were lower than 100 μM. In conclusion, our study suggested that endophytic fungi of D. officinale are great potential resources to discover novel agents for preventing or treating pathogens and tumors.

Cryptococcus laurentii fungemia.

PubMed

Banerjee, P; Haider, M; Trehan, V; Mishra, B; Thakur, A; Dogra, V; Loomba, P

2013-01-01

In the last few years there has been an increasing incidence of infection due to non-neoformans Cryptococcus spp. especially in immunocompromised host. Cryptococcus laurentii is a non-neoformans Cryptococcus which has rarely been known to cause bacteremia and pulmonary infection in humans. Here we report a case of fungemia due to Cryptococcus laurentii.

Bacterial and fungal flora of seagull droppings in Jersey

PubMed Central

Cragg, John; Clayton, Yvonne M.

1971-01-01

In Jersey 166 fresh and 122 dried seagull droppings were obtained and studied locally and in London for the presence of bacteria and fungi of potentially pathogenic nature. There were no salmonella or shigella bacteria isolated from the two groups but there was a high proportion of Candida albicans obtained from the fresh material (21·7%) and only 1·6% from the dry faeces. Cryptococcus neoformans and Histoplasma capsulatum were not found in either the dry or fresh droppings. The normal bacterial and fungal flora of the seagull was established and it is considered that the C. albicans in fresh gull droppings would not materially increase albicans infections in man. PMID:5104846

Establishing an unusual cell type: How to make a dikaryon

PubMed Central

Kruzel, Emilia K.; Hull, Christina M.

2010-01-01

Summary The dikaryons of basidiomycete fungi represent an unusual cell type required for complete sexual development. Dikaryon formation occurs via the activities of cell type-specific homeodomain transcription factors, which form regulatory complexes to establish the dikaryotic state. Decades of classical genetic and cell biological studies in mushrooms have provided a foundation for more recent molecular studies in the pathogenic species Ustilago maydis and Cryptococcus neoformans. Studies in these systems have revealed novel mechanisms of regulation that function downstream of classic homeodomain complexes to ensure that dikaryons are established and propagated. Comparisons of these dikaryon-specific networks promise to reveal the nature of regulatory network evolution and the adaptations responsible for driving complex eukaryotic development. PMID:21036099

Industrially Important Carbohydrate Degrading Enzymes from Yeasts: Pectinases, Chitinases, and β-1,3-Glucanases

NASA Astrophysics Data System (ADS)

Gummadi, Sathyanarayana N.; Kumar, D. Sunil; Dash, Swati S.; Sahu, Santosh Kumar

Polysaccharide degrading enzymes are hydrolytic enzymes, which have a lot of industrial potential and also play a crucial role in carbon recycling. Pectinases, chitinases and glucanases are the three major polysaccharide degrading enzymes found abundantly in nature and these enzymes are mainly produced by fungal strains. Production of these enzymes by yeasts is advantageous over fungi, because the former are easily amenable to genetic manipulations and time required for growth and production is less than that of the latter. Several yeasts belonging to Saccharomyces, Pichia, Rhodotorula and Cryptococcus produce extracellular pectinases, glucanases and chitinases. This chapter emphasizes on the biological significance of these enzymes, their production and their industrial applications.

Cryptococcus neoformans and Cryptococcus gattii, the Etiologic Agents of Cryptococcosis

PubMed Central

Kwon-Chung, Kyung J.; Fraser, James A.; Doering, Tamara L.; Wang, Zhou; Janbon, Guilhem; Idnurm, Alexander; Bahn, Yong-Sun

2014-01-01

Cryptococcus neoformans and Cryptococcus gattii are the two etiologic agents of cryptococcosis. They belong to the phylum Basidiomycota and can be readily distinguished from other pathogenic yeasts such as Candida by the presence of a polysaccharide capsule, formation of melanin, and urease activity, which all function as virulence determinants. Infection proceeds via inhalation and subsequent dissemination to the central nervous system to cause meningoencephalitis. The most common risk for cryptococcosis caused by C. neoformans is AIDS, whereas infections caused by C. gattii are more often reported in immunocompetent patients with undefined risk than in the immunocompromised. There have been many chapters, reviews, and books written on C. neoformans. The topics we focus on in this article include species description, pathogenesis, life cycle, capsule, and stress response, which serve to highlight the specializations in virulence that have occurred in this unique encapsulated melanin-forming yeast that causes global deaths estimated at more than 600,000 annually. PMID:24985132

Systematic review of severe acute liver injury caused by terbinafine.

PubMed

Yan, Jun; Wang, Xiaolin; Chen, Shengli

2014-08-01

Terbinafine is an effective antimicrobial agent against dermatophytes, cryptococcus and other fungi. It is the preferred drug to treat onychomycosis. However, severe acute hepatitis from oral terbinafine administration has been recently reported. To describe a representative case, and review the literature regarding the best evidence on treatment and prognosis of severe acute hepatitis caused by oral terbinafine. The literature was searched for publications on severe hepatitis caused by terbinafine using MEDLINE, China Biology Medicine Disc, and the VIP Medical Information Resource System. Related references were searched manually. Seventeen English and three Chinese references of case reports were included after eliminating duplicate publications. No randomized control studies were found. Liver enzyme levels were found to have been increased significantly. Abdominal ultrasound demonstrated cholestasis. Severe acute liver injury is a known, but unusual complication of terbinafine exposure. The prognosis is often good with appropriate treatment. Liver function assessment before treatment and periodic monitoring 4-6 weeks after initiation of treatment is recommended.

Antifungal dimeric chalcone derivative kamalachalcone E from Mallotus philippinensis.

PubMed

Kulkarni, Roshan R; Tupe, Santosh G; Gample, Suwarna P; Chandgude, Macchindra G; Sarkar, Dhiman; Deshpande, Mukund V; Joshi, Swati P

2014-01-01

From the red coloured extract (Kamala) prepared through acetone extraction of the fresh whole uncrushed fruits of Mallotus philippinensis, one new dimeric chalcone (1) along with three known compounds 1-(5,7-dihydroxy-2,2,6-trimethyl-2H-1-benzopyran-8-yl)-3-phenyl-2-propen-1-one (2), rottlerin (3) and 4'-hydroxyrottlerin (4) were isolated. The structure of compound 1 was elucidated by 1D and 2D NMR analyses that included HSQC, HMBC, COSY and ROESY experiments along with the literature comparison. Compounds 1-4 were evaluated for antifungal activity against different human pathogenic yeasts and filamentous fungi. The antiproliferative activity of the compounds was evaluated against Thp-1 cell lines. Compounds 1 and 2 both exhibited IC50 of 8, 4 and 16 μg/mL against Cryptococcus neoformans PRL518, C. neoformans ATCC32045 and Aspergillus fumigatus, respectively. Compound 4, at 100 μg/mL, showed 54% growth inhibition of Thp-1 cell lines.

Rapid identification of fungal pathogens in BacT/ALERT, BACTEC, and BBL MGIT media using polymerase chain reaction and DNA sequencing of the internal transcribed spacer regions.

PubMed

Pryce, Todd M; Palladino, Silvano; Price, Diane M; Gardam, Dianne J; Campbell, Peter B; Christiansen, Keryn J; Murray, Ronan J

2006-04-01

We report a direct polymerase chain reaction/sequence (d-PCRS)-based method for the rapid identification of clinically significant fungi from 5 different types of commercial broth enrichment media inoculated with clinical specimens. Media including BacT/ALERT FA (BioMérieux, Marcy l'Etoile, France) (n = 87), BACTEC Plus Aerobic/F (Becton Dickinson, Microbiology Systems, Sparks, MD) (n = 16), BACTEC Peds Plus/F (Becton Dickinson) (n = 15), BACTEC Lytic/10 Anaerobic/F (Becton Dickinson) (n = 11) bottles, and BBL MGIT (Becton Dickinson) (n = 11) were inoculated with specimens from 138 patients. A universal DNA extraction method was used combining a novel pretreatment step to remove PCR inhibitors with a column-based DNA extraction kit. Target sequences in the noncoding internal transcribed spacer regions of the rRNA gene were amplified by PCR and sequenced using a rapid (24 h) automated capillary electrophoresis system. Using sequence alignment software, fungi were identified by sequence similarity with sequences derived from isolates identified by upper-level reference laboratories or isolates defined as ex-type strains. We identified Candida albicans (n = 14), Candida parapsilosis (n = 8), Candida glabrata (n = 7), Candida krusei (n = 2), Scedosporium prolificans (n = 4), and 1 each of Candida orthopsilosis, Candida dubliniensis, Candida kefyr, Candida tropicalis, Candida guilliermondii, Saccharomyces cerevisiae, Cryptococcus neoformans, Aspergillus fumigatus, Histoplasma capsulatum, and Malassezia pachydermatis by d-PCRS analysis. All d-PCRS identifications from positive broths were in agreement with the final species identification of the isolates grown from subculture. Earlier identification of fungi using d-PCRS may facilitate prompt and more appropriate antifungal therapy.

Two Distinct Approaches for CRISPR-Cas9-Mediated Gene Editing in Cryptococcus neoformans and Related Species.

PubMed

Wang, Ping

2018-06-27

Cryptococcus neoformans and related species are encapsulated basidiomycetous fungi that cause meningoencephalitis in individuals with immune deficiency. This pathogen has a tractable genetic system; however, gene disruption via electroporation remains difficult, while biolistic transformation is often limited by lack of multiple genetic markers and the high initial cost of equipment. The approach using clustered regularly interspaced short palindromic repeats (CRISPR) and CRISPR-associated protein 9 (Cas9) has become the technology of choice for gene editing in many organisms due to its simplicity, efficiency, and versatility. The technique has been successfully demonstrated in C. neoformans and Cryptococcus deneoformans in which two DNA plasmids expressing either the Streptococcus pyogenes CAS9 gene or the guide RNA (gRNA) were employed. However, potential adverse effects due to constitutive expression and the time-consuming process of constructing vectors to express each gRNA remain as a primary barrier for wide adaptation. This report describes the delivery of preassembled CRISPR-Cas9-gRNA ribonucleoproteins (RNPs) via electroporation that is able to generate edited mutant alleles. RNP-mediated CRISPR-Cas9 was used to replace the wild-type GIB2 gene encoding a Gβ-like/RACK1 Gib2 protein with a gib2 :: NAT allele via homologous recombination in both C. neoformans and C. deneoformans In addition, a DNA plasmid (pCnCas9:U6-gRNA) that expresses both Cas9 and gRNA, allowing for convenient yet low-cost DNA-mediated gene editing, is described. pCnCas9:U6-gRNA contains an endogenous U6 promoter for gRNA expression and restriction sites for one-step insertion of a gRNA. These approaches and resources provide new opportunities to accelerate genetic studies of Cryptococcus species. IMPORTANCE For genetic studies of the Cryptococcus genus, generation of mutant strains is often hampered by a limited number of selectable genetic markers, the tedious process of vector construction, side effects, and other limitations, such as the high cost of acquiring a particle delivery system. CRISPR-Cas9 technology has been demonstrated in Cryptococcus for genome editing. However, it remains labor-intensive and time-consuming since it requires the identification of a suitable type III RNA polymerase promoter for gRNA expression. In addition, there may be potential adverse effects caused by constitutive expressions of Cas9 and gRNA. Here, I report the use of a ribonucleoprotein-mediated CRISPR-Cas9 technique for genome editing of C. neoformans and related species. Together with the custom-constructed pCnCas9:U6-gRNA vector that allows low-cost and time-saving DNA-based CRISPR-Cas9, my approach adds to the molecular toolbox for dissecting the molecular mechanism of pathogenesis in this important group of fungal pathogens. Copyright © 2018 Wang.

Influenza A Virus as a Predisposing Factor for Cryptococcosis

PubMed Central

Oliveira, Lorena V. N.; Costa, Marliete C.; Magalhães, Thaís F. F.; Bastos, Rafael W.; Santos, Patrícia C.; Carneiro, Hellem C. S.; Ribeiro, Noelly Q.; Ferreira, Gabriella F.; Ribeiro, Lucas S.; Gonçalves, Ana P. F.; Fagundes, Caio T.; Pascoal-Xavier, Marcelo A.; Djordjevic, Julianne T.; Sorrell, Tania C.; Souza, Daniele G.; Machado, Alexandre M. V.; Santos, Daniel A.

2017-01-01

Influenza A virus (IAV) infects millions of people annually and predisposes to secondary bacterial infections. Inhalation of fungi within the Cryptococcus complex causes pulmonary disease with secondary meningo-encephalitis. Underlying pulmonary disease is a strong risk factor for development of C. gattii cryptococcosis though the effect of concurrent infection with IAV has not been studied. We developed an in vivo model of Influenza A H1N1 and C. gattii co-infection. Co-infection resulted in a major increase in morbidity and mortality, with severe lung damage and a high brain fungal burden when mice were infected in the acute phase of influenza multiplication. Furthermore, IAV alters the host response to C. gattii, leading to recruitment of significantly more neutrophils and macrophages into the lungs. Moreover, IAV induced the production of type 1 interferons (IFN-α4/β) and the levels of IFN-γ were significantly reduced, which can be associated with impairment of the immune response to Cryptococcus during co-infection. Phagocytosis, killing of cryptococci and production of reactive oxygen species (ROS) by IAV-infected macrophages were reduced, independent of previous IFN-γ stimulation, leading to increased proliferation of the fungus within macrophages. In conclusion, IAV infection is a predisposing factor for severe disease and adverse outcomes in mice co-infected with C. gattii. PMID:29018774

Fisetin as a promising antifungal agent against Cryptocococcus neoformans species complex.

PubMed

Reis, M P C; Carvalho, C R C; Andrade, F A; Fernandes, O F L; Arruda, W; Silva, M R R

2016-08-01

The aim of this study was to investigate the mechanisms of action of fisetin, a flavonol with antifungal activity previously evaluated against the Cryptococcus neoformans species complex. Ergosterol content and flow cytometry analysis were determined for the C. neoformans species complex in the presence of fisetin and ultrastructural analysis of morphology was performed on Cryptococcus gattii and C. neoformans. Decrease in the total cellular ergosterol content after exposure to fisetin ranged from 25·4% after exposure to 128 μg ml(-1) to 21·6% after exposure to 64 μg ml(-1) of fisetin compared with the control (without fisetin). The fisetin effects obtained with flow cytometry showed metabolic impairment, and alterations in its normal morphology caused by fisetin in C. neoformans cells were verified using scanning electron microscopy. Fisetin is a compound that acts in the biosynthesis of ergosterol. Flow cytometry showed that fisetin reduced viability of the metabolically active cells of C. gattii, while morphological changes explain the action of fisetin in inhibiting growth of these fungi. This study supports the idea that fisetin may represent a good starting point for the development of future therapeutic substances for cryptococcosis. © 2016 The Society for Applied Microbiology.

Cell wall chitosan is necessary for virulence in the opportunistic pathogen Cryptococcus neoformans.

PubMed

Baker, Lorina G; Specht, Charles A; Lodge, Jennifer K

2011-09-01

Cryptococcus neoformans is an opportunistic fungal pathogen that causes meningoencephalitis. Its cell wall is composed of glucans, proteins, chitin, and chitosan. Multiple genetic approaches have defined a chitosan-deficient syndrome that includes slow growth and decreased cell integrity. Here we demonstrate chitosan is necessary for virulence and persistence in the mammalian host.

Rapid Identification of Cryptococcus neoformans var. grubii, C. neoformans var. neoformans, and C. gattii by Use of Rapid Biochemical Tests, Differential Media, and DNA Sequencing ▿

PubMed Central

McTaggart, Lisa; Richardson, Susan E.; Seah, Christine; Hoang, Linda; Fothergill, Annette; Zhang, Sean X.

2011-01-01

Rapid identification of Cryptococcus neoformans var. grubii, Cryptococcus neoformans var. neoformans, and Cryptococcus gattii is imperative for facilitation of prompt treatment of cryptococcosis and for understanding the epidemiology of the disease. Our purpose was to evaluate a test algorithm incorporating commercial rapid biochemical tests, differential media, and DNA sequence analysis that will allow us to differentiate these taxa rapidly and accurately. We assessed 147 type, reference, and clinical isolates, including 6 other Cryptococcus spp. (10 isolates) and 14 other yeast species (24 isolates), using a 4-hour urea broth test (Remel), a 24-hour urea broth test (Becton Dickinson), a 4-hour caffeic acid disk test (Hardy Diagnostics and Remel), 40- to 44-hour growth assessment on l-canavanine glycine bromothymol blue (CGB) agar, and intergenic spacer (IGS) sequence analysis. All 123 Cryptococcus isolates hydrolyzed urea, along with 7 isolates of Rhodotorula and Trichosporon. Eighty-five of 86 C. neoformans (99%) and 26 of 27 C. gattii (96%) isolates had positive caffeic acid results, unlike the other cryptococci (0/10) and yeast species (0/24). Together, these two tests positively identified virtually all C. neoformans/C. gattii isolates (98%) within 4 h. CGB agar or IGS sequencing further differentiated these isolates within 48 h. On CGB, 25 of 27 (93%) C. gattii strains induced a blue color change, in contrast to 0 of 86 C. neoformans isolates. Neighbor-joining cluster analysis of IGS sequences differentiated C. neoformans var. grubii, C. neoformans var. neoformans, and C. gattii. Based on these results, we describe a rapid identification algorithm for use in a microbiology laboratory to distinguish clinically relevant Cryptococcus spp. PMID:21593254

Rapid identification of Cryptococcus neoformans var. grubii, C. neoformans var. neoformans, and C. gattii by use of rapid biochemical tests, differential media, and DNA sequencing.

PubMed

McTaggart, Lisa; Richardson, Susan E; Seah, Christine; Hoang, Linda; Fothergill, Annette; Zhang, Sean X

2011-07-01

Rapid identification of Cryptococcus neoformans var. grubii, Cryptococcus neoformans var. neoformans, and Cryptococcus gattii is imperative for facilitation of prompt treatment of cryptococcosis and for understanding the epidemiology of the disease. Our purpose was to evaluate a test algorithm incorporating commercial rapid biochemical tests, differential media, and DNA sequence analysis that will allow us to differentiate these taxa rapidly and accurately. We assessed 147 type, reference, and clinical isolates, including 6 other Cryptococcus spp. (10 isolates) and 14 other yeast species (24 isolates), using a 4-hour urea broth test (Remel), a 24-hour urea broth test (Becton Dickinson), a 4-hour caffeic acid disk test (Hardy Diagnostics and Remel), 40- to 44-hour growth assessment on l-canavanine glycine bromothymol blue (CGB) agar, and intergenic spacer (IGS) sequence analysis. All 123 Cryptococcus isolates hydrolyzed urea, along with 7 isolates of Rhodotorula and Trichosporon. Eighty-five of 86 C. neoformans (99%) and 26 of 27 C. gattii (96%) isolates had positive caffeic acid results, unlike the other cryptococci (0/10) and yeast species (0/24). Together, these two tests positively identified virtually all C. neoformans/C. gattii isolates (98%) within 4 h. CGB agar or IGS sequencing further differentiated these isolates within 48 h. On CGB, 25 of 27 (93%) C. gattii strains induced a blue color change, in contrast to 0 of 86 C. neoformans isolates. Neighbor-joining cluster analysis of IGS sequences differentiated C. neoformans var. grubii, C. neoformans var. neoformans, and C. gattii. Based on these results, we describe a rapid identification algorithm for use in a microbiology laboratory to distinguish clinically relevant Cryptococcus spp.

High prevalence of fastidious bacteria in 1520 cases of uveitis of unknown etiology.

PubMed

Drancourt, Michel; Berger, Pierre; Terrada, Céline; Bodaghi, Bahram; Conrath, John; Raoult, Didier; LeHoang, Phuc

2008-05-01

The etiologic evaluation of uveitis is frequently unsuccessful when noninvasive methods are used. We conducted a prospective study to evaluate systematic screening for pathogens of uveitis. All patients with uveitis referred to the participating tertiary ophthalmology departments from January 2001 to September 2007 underwent intraocular and serum specimen collection. The standardized protocol for laboratory investigations included universal polymerase chain reaction (PCR)-based detection of any bacteria and mycoses, specific PCR-based detection of fastidious (difficult-to-grow) bacteria and herpes viruses, and culture of vitreous fluid. Sera were tested for fastidious bacteria. Among the 1321 included patients (1520 specimens), infection was diagnosed in 147 (11.1%) patients: 78 (53%) were caused by fastidious bacteria that included spirochetes, Bartonella species, intracellular bacteria (Chlamydia species, Rickettsia species, Coxiella burnetii), and Tropheryma whipplei; 18 by herpes viruses; and 9 by fungi. Bartonella quintana, Coxiella burnetii, Paracoccus yeei, Aspergillus oryzae, and Cryptococcus albidus were found to be associated with uveitis for the first time, to our knowledge. We recommend applying a 1-step diagnostic procedure that incorporates intraocular, specific microbial PCR with serum analyses in tertiary centers to determine the etiology of uveitis.

High-Resolution Genetics Identifies the Lipid Transfer Protein Sec14p as Target for Antifungal Ergolines

PubMed Central

Cotesta, Simona; Perruccio, Francesca; Knapp, Britta; Fu, Yue; Studer, Christian; Pries, Verena; Riedl, Ralph; Helliwell, Stephen B.; Petrovic, Katarina T.; Movva, N. Rao; Sanglard, Dominique; Tao, Jianshi; Hoepfner, Dominic

2016-01-01

Invasive infections by fungal pathogens cause more deaths than malaria worldwide. We found the ergoline compound NGx04 in an antifungal screen, with selectivity over mammalian cells. High-resolution chemogenomics identified the lipid transfer protein Sec14p as the target of NGx04 and compound-resistant mutations in Sec14p define compound-target interactions in the substrate binding pocket of the protein. Beyond its essential lipid transfer function in a variety of pathogenic fungi, Sec14p is also involved in secretion of virulence determinants essential for the pathogenicity of fungi such as Cryptococcus neoformans, making Sec14p an attractive antifungal target. Consistent with this dual function, we demonstrate that NGx04 inhibits the growth of two clinical isolates of C. neoformans and that NGx04-related compounds have equal and even higher potency against C. neoformans. Furthermore NGx04 analogues showed fungicidal activity against a fluconazole resistant C. neoformans strain. In summary, we present genetic evidence that NGx04 inhibits fungal Sec14p and initial data supporting NGx04 as a novel antifungal starting point. PMID:27855158

Linear Epitopes of Paracoccidioides brasiliensis and Other Fungal Agents of Human Systemic Mycoses As Vaccine Candidates

PubMed Central

Travassos, Luiz R.; Taborda, Carlos P.

2017-01-01

Dimorphic fungi are agents of systemic mycoses associated with significant morbidity and frequent lethality in the Americas. Among the pathogenic species are Paracoccidioides brasiliensis and Paracoccidioides lutzii, which predominate in South America; Histoplasma capsulatum, Coccidioides posadasii, and Coccidioides immitis, and the Sporothrix spp. complex are other important pathogens. Associated with dimorphic fungi other important infections are caused by yeast such as Candida spp. and Cryptococcus spp. or mold such as Aspergillus spp., which are also fungal agents of deadly infections. Nowadays, the actual tendency of therapy is the development of a pan-fungal vaccine. This is, however, not easy because of the complexity of eukaryotic cells and the particularities of different species and isolates. Albeit there are several experimental vaccines being studied, we will focus mainly on peptide vaccines or epitopes of T-cell receptors inducing protective fungal responses. These peptides can be carried by antibody inducing β-(1,3)-glucan oligo or polysaccharides, or be mixed with them for administration. The present review discusses the efficacy of linear peptide epitopes in the context of antifungal immunization and vaccine proposition. PMID:28344577

Cryptococcus species (Tremellales) from glacial biomes in the southern (Patagonia) and northern (Svalbard) hemispheres.

PubMed

de Garcia, Virginia; Zalar, Polona; Brizzio, Silvia; Gunde-Cimerman, Nina; van Broock, María

2012-11-01

Cryptococcus species (Basidiomycota) were isolated as the predominant yeast from glacial biomes of both Patagonia (Argentina) and the Svalbard archipelago (Norway). For a selected group of Cryptococcus belonging to Tremellales, assimilative profile, production of extracellular hydrolytic enzymes and ribosomal DNA internal transcribed spacer and large subunit (D1/D2) sequences were analysed. Cryptococcus victoriae, which was originally described from Antarctica, was the most frequently found species at both locations. High variability within the species was observed and described at the genotypic and phenotypic levels, two newly described species were found in both Patagonia and Svalbard: Cryptococcus fonsecae and Cryptococcus psychrotolerans. Two other new species were found only in Patagonia: Cryptococcus frias and Cryptococcus tronadorensis. Three additional new taxa were found, but they are not named as they were only represented by single isolates. © 2012 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.

False-positive cerebrospinal fluid cryptococcus antigen in Libman-Sacks endocarditis.

PubMed

Isseh, Iyad N; Bourgi, Kassem; Nakhle, Asaad; Ali, Mahmoud; Zervos, Marcus J

2016-12-01

Cryptococcus meningoencephalitis is a serious opportunistic infection associated with high morbidity and mortality in immunocompromised hosts, particularly patients with advanced AIDS disease. The diagnosis is established through cerebrospinal fluid (CSF) cryptococcus antigen detection and cultures. Cryptococcus antigen testing is usually the initial test of choice due its high sensitivity and specificity along with the quick availability of the results. We hereby report a case of a false-positive CSF cryptococcus antigen assay in a patient with systemic lupus erythematosus presenting with acute confusion. While initial CSF evaluation revealed a positive cryptococcus antigen assay, the patient's symptoms were inconsistent with cryptococcus meningoencephalitis. A repeat CSF evaluation, done 3 days later, revealed a negative CSF cryptococcus antigen assay. Given the patient's active lupus disease and the elevated antinuclear antibody titers, we believe that the initial positive result was a false positive caused by interference from autoantibodies.

Cellular and Molecular Defects Underlying Invasive Fungal Infections—Revelations from Endemic Mycoses

PubMed Central

Lee, Pamela P.; Lau, Yu-Lung

2017-01-01

The global burden of fungal diseases has been increasing, as a result of the expanding number of susceptible individuals including people living with human immunodeficiency virus (HIV), hematopoietic stem cell or organ transplant recipients, patients with malignancies or immunological conditions receiving immunosuppressive treatment, premature neonates, and the elderly. Opportunistic fungal pathogens such as Aspergillus, Candida, Cryptococcus, Rhizopus, and Pneumocystis jiroveci are distributed worldwide and constitute the majority of invasive fungal infections (IFIs). Dimorphic fungi such as Histoplasma capsulatum, Coccidioides spp., Paracoccidioides spp., Blastomyces dermatiditis, Sporothrix schenckii, Talaromyces (Penicillium) marneffei, and Emmonsia spp. are geographically restricted to their respective habitats and cause endemic mycoses. Disseminated histoplasmosis, coccidioidomycosis, and T. marneffei infection are recognized as acquired immunodeficiency syndrome (AIDS)-defining conditions, while the rest also cause high rate of morbidities and mortalities in patients with HIV infection and other immunocompromised conditions. In the past decade, a growing number of monogenic immunodeficiency disorders causing increased susceptibility to fungal infections have been discovered. In particular, defects of the IL-12/IFN-γ pathway and T-helper 17-mediated response are associated with increased susceptibility to endemic mycoses. In this review, we put together the various forms of endemic mycoses on the map and take a journey around the world to examine how cellular and molecular defects of the immune system predispose to invasive endemic fungal infections, including primary immunodeficiencies, individuals with autoantibodies against interferon-γ, and those receiving biologic response modifiers. Though rare, these conditions provide importance insights to host defense mechanisms against endemic fungi, which can only be appreciated in unique climatic and geographical regions. PMID:28702025

Solid-state NMR Reveals the Carbon-based Molecular Architecture of Cryptococcus neoformans Fungal Eumelanins in the Cell Wall*

PubMed Central

Chatterjee, Subhasish; Prados-Rosales, Rafael; Itin, Boris; Casadevall, Arturo; Stark, Ruth E.

2015-01-01

Melanin pigments protect against both ionizing radiation and free radicals and have potential soil remediation capabilities. Eumelanins produced by pathogenic Cryptococcus neoformans fungi are virulence factors that render the fungal cells resistant to host defenses and certain antifungal drugs. Because of their insoluble and amorphous characteristics, neither the pigment bonding framework nor the cellular interactions underlying melanization of C. neoformans have yielded to comprehensive molecular-scale investigation. This study used the C. neoformans requirement of exogenous obligatory catecholamine precursors for melanization to produce isotopically enriched pigment “ghosts” and applied 2D 13C-13C correlation solid-state NMR to reveal the carbon-based architecture of intact natural eumelanin assemblies in fungal cells. We demonstrated that the aliphatic moieties of solid C. neoformans melanin ghosts include cell-wall components derived from polysaccharides and/or chitin that are associated proximally with lipid membrane constituents. Prior to development of the mature aromatic fungal pigment, these aliphatic moieties form a chemically resistant framework that could serve as the scaffold for melanin synthesis. The indole-based core aromatic moieties show interconnections that are consistent with proposed melanin structures consisting of stacked planar assemblies, which are associated spatially with the aliphatic scaffold. The pyrrole aromatic carbons of the pigments bind covalently to the aliphatic framework via glycoside or glyceride functional groups. These findings establish that the structure of the pigment assembly changes with time and provide the first biophysical information on the mechanism by which melanin is assembled in the fungal cell wall, offering vital insights that can advance the design of bioinspired conductive nanomaterials and novel therapeutics. PMID:25825492

Solid-state NMR Reveals the Carbon-based Molecular Architecture of Cryptococcus neoformans Fungal Eumelanins in the Cell Wall.

PubMed

Chatterjee, Subhasish; Prados-Rosales, Rafael; Itin, Boris; Casadevall, Arturo; Stark, Ruth E

2015-05-29

Melanin pigments protect against both ionizing radiation and free radicals and have potential soil remediation capabilities. Eumelanins produced by pathogenic Cryptococcus neoformans fungi are virulence factors that render the fungal cells resistant to host defenses and certain antifungal drugs. Because of their insoluble and amorphous characteristics, neither the pigment bonding framework nor the cellular interactions underlying melanization of C. neoformans have yielded to comprehensive molecular-scale investigation. This study used the C. neoformans requirement of exogenous obligatory catecholamine precursors for melanization to produce isotopically enriched pigment "ghosts" and applied 2D (13)C-(13)C correlation solid-state NMR to reveal the carbon-based architecture of intact natural eumelanin assemblies in fungal cells. We demonstrated that the aliphatic moieties of solid C. neoformans melanin ghosts include cell-wall components derived from polysaccharides and/or chitin that are associated proximally with lipid membrane constituents. Prior to development of the mature aromatic fungal pigment, these aliphatic moieties form a chemically resistant framework that could serve as the scaffold for melanin synthesis. The indole-based core aromatic moieties show interconnections that are consistent with proposed melanin structures consisting of stacked planar assemblies, which are associated spatially with the aliphatic scaffold. The pyrrole aromatic carbons of the pigments bind covalently to the aliphatic framework via glycoside or glyceride functional groups. These findings establish that the structure of the pigment assembly changes with time and provide the first biophysical information on the mechanism by which melanin is assembled in the fungal cell wall, offering vital insights that can advance the design of bioinspired conductive nanomaterials and novel therapeutics. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

Antifungal susceptibilities of Candida, Cryptococcus neoformans and Aspergillus fumigatus from the Asia and Western Pacific region: data from the SENTRY antifungal surveillance program (2010-2012).

PubMed

Pfaller, Michael A; Messer, Shawn A; Jones, Ronald N; Castanheira, Mariana

2015-09-01

The SENTRY Antifungal Surveillance Program monitors global susceptibility rates of newer and established antifungal agents. We report the in vitro activity of seven antifungal agents against 496 contemporary clinical isolates of yeasts and molds. The isolates were obtained from 20 laboratories in the Asia-Western Pacific (APAC) region during 2010 through 2012. Anidulafungin, caspofungin, micafungin, fluconazole, itraconazole, posaconazole and voriconazole were susceptibility tested using CLSI methods and species-specific interpretive criteria. Sequencing of fks hot spots was performed for echinocandin-resistant strains. Isolates included 13 species of Candida (n=460), 5 species of non-Candida yeasts (21), 5 species of Aspergillus (11) and 4 other molds. Echinocandin resistance was uncommon among eight species of Candida and was only detected in three isolates of Candida glabrata, two from Australia harboring mutations in fks1 (F625S) and fks2 (S663P). Resistance to the azoles was much more common and was observed among all species with the exception of Candida dubliniensis. Fluconazole resistance rates observed with C. glabrata (6.8%) was comparable to that seen with Candida parapsilosis (5.7%) and Candida tropicalis (3.6%). Cross resistance among the triazoles was seen with each of these three species. The mold-active azoles and the echinocandins were all active against isolates of Aspergillus fumigatus. Azole resistance was not detected among the isolates of Cryptococcus neoformans. Antifungal resistance is uncommon among isolates of fungi causing invasive fungal infections in the APAC region. As in other regions of the world, emerging resistance to the echinocandins among invasive isolates of C. glabrata bears close monitoring.

Cell Wall Chitosan Is Necessary for Virulence in the Opportunistic Pathogen Cryptococcus neoformans ▿

PubMed Central

Baker, Lorina G.; Specht, Charles A.; Lodge, Jennifer K.

2011-01-01

Cryptococcus neoformans is an opportunistic fungal pathogen that causes meningoencephalitis. Its cell wall is composed of glucans, proteins, chitin, and chitosan. Multiple genetic approaches have defined a chitosan-deficient syndrome that includes slow growth and decreased cell integrity. Here we demonstrate chitosan is necessary for virulence and persistence in the mammalian host. PMID:21784998

Molecules at the interface of Cryptococcus and the host that determine disease susceptibility.

PubMed

Wozniak, Karen L; Olszewski, Michal A; Wormley, Floyd L

2015-05-01

Cryptococcus neoformans and Cryptococcus gattii, the predominant etiological agents of cryptococcosis, are fungal pathogens that cause disease ranging from a mild pneumonia to life-threatening infections of the central nervous system (CNS). Resolution or exacerbation of Cryptococcus infection is determined following complex interactions of several host and pathogen derived factors. Alternatively, interactions between the host and pathogen may end in an impasse resulting in the establishment of a sub-clinical Cryptococcus infection. The current review addresses the delicate interaction between the host and Cryptococcus-derived molecules that determine resistance or susceptibility to infection. An emphasis will be placed on data highlighted at the recent 9th International Conference on Cryptococcus and Cryptococcosis (ICCC). Copyright © 2015. Published by Elsevier Inc.

Crystal structure of homoisocitrate dehydrogenase from Schizosaccharomyces pombe

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bulfer, Stacie L.; Hendershot, Jenna M.; Trievel, Raymond C.

Lysine biosynthesis in fungi, euglena, and certain archaebacteria occurs through the {alpha}-aminoadipate pathway. Enzymes in the first steps of this pathway have been proposed as potential targets for the development of antifungal therapies, as they are absent in animals but are conserved in several pathogenic fungi species, including Candida, Cryptococcus, and Aspergillus. One potential antifungal target in the {alpha}-aminoadipate pathway is the third enzyme in the pathway, homoisocitrate dehydrogenase (HICDH), which catalyzes the divalent metal-dependent conversion of homoisocitrate to 2-oxoadipate (2-OA) using nicotinamide adenine dinucleotide (NAD{sup +}) as a cofactor. HICDH belogns to a family of {beta}-hydroxyacid oxidative decarboxylases thatmore » includes malate dehydrogenase, tartrate dehydrogenase, 6-phosphogluconate dehydrogenase, isocitrate dehydrogenase (ICDH), and 3-isopropylmalte dehydrogenase (IPMDH). ICDH and IPMDH are well-characterized enzymes that catalyze the decarboxylation of isocitrate to yield 2-oxoglutarate (2-OG) in the citric acid cycle and the conversion of 3-isopropylmalate to 2-oxoisovalerate in the leucine biosynthetic pathway, respectively. Recent structural and biochemical studies of HICDH reveal that this enzyme shares sequence, structural, and mechanistic homology with ICDH and IPMDH. To date, the only published structures of HICDH are from the archaebacteria Thermus thermophilus (TtHICDH). Fungal HICDHs diverge from TtHICDH in several aspects, including their thermal stability, oligomerization state, and substrate specificity, thus warranting further characterization. To gain insights into these differences, they determined crystal structures of a fungal Schizosaccharomyces pombe HICDH (SpHICDH) as an apoenzyme and as a binary complex with additive tripeptide glycyl-glycyl-glycine (GGG) to 1.55 {angstrom} and 1.85 {angstrom} resolution, respectively. Finally, a comparison of the SpHICDH and TtHICDH structures reveal differences in their active sites that help explain the variations in their respective substrate specificities.« less

Essential oil composition and antimicrobial activity of Santiria trimera bark.

PubMed

Martins, A P; Salgueiro, L R; Gonçalves, M J; Proença da Cunha, A; Vila, R; Cañigueral, S

2003-01-01

The composition and the antimicrobial activity of the bark oil of Santiria trimera (Oliv.) Aubrév., a plant widely used by the traditional healers in S. Tomé and Príncipe, especially for wound healing, are reported for the first time. The analysis of the essential oil was carried out by GC and GC-MS. The oil contains a high content of monoterpenes, alpha-pinene (66.6 %) being the major constituent, followed by beta-pinene (20.0 %). The essential oil was active against both bacteria and fungi strains, except Staphylococcus epidermidis and Aspergillus niger. It exhibited significant antimicrobial activity against Proteus vulgaris and Cryptococcus neoformans with MICs values of 1.11 microl/ml and lower than 0.71 microl/ml, respectively.

Cutinase-Like Enzyme from the Yeast Cryptococcus sp. Strain S-2 Hydrolyzes Polylactic Acid and Other Biodegradable Plastics

PubMed Central

Masaki, Kazuo; Kamini, Numbi Ramudu; Ikeda, Hiroko; Iefuji, Haruyuki

2005-01-01

A purified lipase from the yeast Cryptococcus sp. strain S-2 exhibited remote homology to proteins belonging to the cutinase family rather than to lipases. This enzyme could effectively degrade the high-molecular-weight compound polylactic acid, as well as other biodegradable plastics, including polybutylene succinate, poly (ɛ-caprolactone), and poly(3-hydroxybutyrate). PMID:16269800

Nutritional Requirements and Their Importance for Virulence of Pathogenic Cryptococcus Species

PubMed Central

Watkins, Rhys A.; Johnston, Simon A.

2017-01-01

Cryptococcus sp. are basidiomycete yeasts which can be found widely, free-living in the environment. Interactions with natural predators, such as amoebae in the soil, are thought to have promoted the development of adaptations enabling the organism to survive inside human macrophages. Infection with Cryptococcus in humans occurs following inhalation of desiccated yeast cells or spore particles and may result in fatal meningoencephalitis. Human disease is caused almost exclusively by the Cryptococcus neoformans species complex, which predominantly infects immunocompromised patients, and the Cryptococcus gattii species complex, which is capable of infecting immunocompetent individuals. The nutritional requirements of Cryptococcus are critical for its virulence in animals. Cryptococcus has evolved a broad range of nutrient acquisition strategies, many if not most of which also appear to contribute to its virulence, enabling infection of animal hosts. In this review, we summarise the current understanding of nutritional requirements and acquisition in Cryptococcus and offer perspectives to its evolution as a significant pathogen of humans. PMID:28974017

Differential Antifungal Activity of Human and Cryptococcal Melanins with Structural Discrepancies

PubMed Central

Correa, Néstor; Covarrubias, Cristian; Rodas, Paula I.; Hermosilla, Germán; Olate, Verónica R.; Valdés, Cristián; Meyer, Wieland; Magne, Fabien; Tapia, Cecilia V.

2017-01-01

Melanin is a pigment found in all biological kingdoms, and plays a key role in protection against ultraviolet radiation, oxidizing agents, and ionizing radiation damage. Melanin exerts an antimicrobial activity against bacteria, fungi, and parasites. We demonstrated an antifungal activity of synthetic and human melanin against Candida sp. The members of the Cryptococcus neoformans and C. gattii species complexes are capsulated yeasts, which cause cryptococcosis. For both species melanin is an important virulence factor. To evaluate if cryptococcal and human melanins have antifungal activity against Cryptococcus species they both were assayed for their antifungal properties and physico-chemical characters. Melanin extracts from human hair and different strains of C. neoformans (n = 4) and C. gattii (n = 4) were investigated. The following minimum inhibitory concentrations were found for different melanins against C. neoformans and C. gattii were (average/range): 13.7/(7.8–15.6) and 19.5/(15.6–31.2) μg/mL, respectively, for human melanin; 273.4/(125–>500) and 367.2/(125.5–>500) μg/mL for C. neoformans melanin and 125/(62.5–250) and 156.2/(62–250) μg/mL for C. gattii melanin. Using Scanning Electron Microscopy we observed that human melanin showed a compact conformation and cryptococcal melanins exposed an amorphous conformation. Infrared spectroscopy (FTIR) showed some differences in the signals related to C-C bonds of the aromatic ring of the melanin monomers. High Performance Liquid Chromatography established differences in the chromatograms of fungal melanins extracts in comparison with human and synthetic melanin, particularly in the retention time of the main compound of fungal melanin extracts and also in the presence of minor unknown compounds. On the other hand, MALDI-TOF-MS analysis showed slight differences in the spectra, specifically the presence of a minor intensity ion in synthetic and human melanin, as well as in some fungal melanin extracts. We conclude that human melanin is more active than the two fungal melanins against Cryptococcus. Although some physico-chemical differences were found, they do not explain the differences in the antifungal activity against Cryptococcus of human and cryptococcal melanins. More detailed studies on the structure should be considered to associate structure and antifungal activity. PMID:28744276

Differential Antifungal Activity of Human and Cryptococcal Melanins with Structural Discrepancies.

PubMed

Correa, Néstor; Covarrubias, Cristian; Rodas, Paula I; Hermosilla, Germán; Olate, Verónica R; Valdés, Cristián; Meyer, Wieland; Magne, Fabien; Tapia, Cecilia V

2017-01-01

Melanin is a pigment found in all biological kingdoms, and plays a key role in protection against ultraviolet radiation, oxidizing agents, and ionizing radiation damage. Melanin exerts an antimicrobial activity against bacteria, fungi, and parasites. We demonstrated an antifungal activity of synthetic and human melanin against Candida sp. The members of the Cryptococcus neoformans and C. gattii species complexes are capsulated yeasts, which cause cryptococcosis. For both species melanin is an important virulence factor. To evaluate if cryptococcal and human melanins have antifungal activity against Cryptococcus species they both were assayed for their antifungal properties and physico-chemical characters. Melanin extracts from human hair and different strains of C. neoformans ( n = 4) and C. gattii ( n = 4) were investigated. The following minimum inhibitory concentrations were found for different melanins against C. neoformans and C. gattii were (average/range): 13.7/(7.8-15.6) and 19.5/(15.6-31.2) μg/mL, respectively, for human melanin; 273.4/(125->500) and 367.2/(125.5->500) μg/mL for C. neoformans melanin and 125/(62.5-250) and 156.2/(62-250) μg/mL for C. gattii melanin. Using Scanning Electron Microscopy we observed that human melanin showed a compact conformation and cryptococcal melanins exposed an amorphous conformation. Infrared spectroscopy (FTIR) showed some differences in the signals related to C-C bonds of the aromatic ring of the melanin monomers. High Performance Liquid Chromatography established differences in the chromatograms of fungal melanins extracts in comparison with human and synthetic melanin, particularly in the retention time of the main compound of fungal melanin extracts and also in the presence of minor unknown compounds. On the other hand, MALDI-TOF-MS analysis showed slight differences in the spectra, specifically the presence of a minor intensity ion in synthetic and human melanin, as well as in some fungal melanin extracts. We conclude that human melanin is more active than the two fungal melanins against Cryptococcus. Although some physico-chemical differences were found, they do not explain the differences in the antifungal activity against Cryptococcus of human and cryptococcal melanins. More detailed studies on the structure should be considered to associate structure and antifungal activity.

Synthesis and Antifungal in Vitro Evaluation of Pyrazolo[3,4-b]pyridines Derivatives Obtained by Aza-Diels-Alder Reaction and Microwave Irradiation.

PubMed

Quiroga, Jairo; Villarreal, Yazmín; Gálvez, Jaime; Ortíz, Alejandro; Insuasty, Braulio; Abonia, Rodrigo; Raimondi, Marcela; Zacchino, Susana

2017-02-01

A series of pyrazolo[3,4-b]pyridines were prepared by a microwave-assisted aza-Diels-Alder reaction between pyrazolylformimidamides 1 and β-nitrostyrenes 2 in toluene as the solvent. This procedure provides a simple one-step and environmentally friendly methodology with good yields for the synthesis of these compounds. All compounds were tested for antifungal activity against two clinically important fungi Candida albicans and Cryptococcus neoformans. Within the compounds of the series bearing a -CH 3 group on the carbon C-3 of the azole ring (3a-e), the compound without a substituent on the p'-phenyl ring (3a), showed the best activity against both fungi, followed by the p'-Br-phenyl (3c). Within the compounds of the series bearing a tert-butyl group in the carbon C-3 of the azole ring (3f-j), the non-substituted p'-compound (3f) was the most active one, followed by (3h) (p'-Br substituted) that showed the best activity against both fungi. The remaining compounds of this sub-series (3g, i, j) showed similar moderate activities. The antifungal activity of the compounds of the series was found to be correlated with a higher log P and a lower dipole moment in the more active compounds.

Cryptococcus albidus infection in a California sea lion (Zalophus californianus).

PubMed

Mcleland, Shannon; Duncan, Colleen; Spraker, Terry; Wheeler, Elizabeth; Lockhart, Shawn R; Gulland, Frances

2012-10-01

Sporadic cases of cryptococcosis have been reported in marine mammals, typically due to Cryptococcus neoformans and, more recently, to Cryptococcus gattii in cetaceans. Cryptococcus albidus, a ubiquitous fungal species not typically considered to be pathogenic, was recovered from a juvenile California sea lion (Zalophus californianus) rescued near San Francisco Bay, California. Yeast morphologically consistent with a Cryptococcus sp. was identified histologically in a lymph node and C. albidus was identified by an rDNA sequence from the lung. Infection with C. albidus was thought to have contributed to mortality in this sea lion, along with concurrent bacterial pneumonia. Cryptococcus albidus should be considered as a potential pathogen with a role in marine mammal morbidity and mortality.

Low Diversity Cryptococcus neoformans Variety grubii Multilocus Sequence Types from Thailand Are Consistent with an Ancestral African Origin

PubMed Central

Simwami, Sitali P.; Khayhan, Kantarawee; Henk, Daniel A.; Aanensen, David M.; Boekhout, Teun; Hagen, Ferry; Brouwer, Annemarie E.; Harrison, Thomas S.; Donnelly, Christl A.; Fisher, Matthew C.

2011-01-01

The global burden of HIV-associated cryptococcal meningitis is estimated at nearly one million cases per year, causing up to a third of all AIDS-related deaths. Molecular epidemiology constitutes the main methodology for understanding the factors underpinning the emergence of this understudied, yet increasingly important, group of pathogenic fungi. Cryptococcus species are notable in the degree that virulence differs amongst lineages, and highly-virulent emerging lineages are changing patterns of human disease both temporally and spatially. Cryptococcus neoformans variety grubii (Cng, serotype A) constitutes the most ubiquitous cause of cryptococcal meningitis worldwide, however patterns of molecular diversity are understudied across some regions experiencing significant burdens of disease. We compared 183 clinical and environmental isolates of Cng from one such region, Thailand, Southeast Asia, against a global MLST database of 77 Cng isolates. Population genetic analyses showed that Thailand isolates from 11 provinces were highly homogenous, consisting of the same genetic background (globally known as VNI) and exhibiting only ten nearly identical sequence types (STs), with three (STs 44, 45 and 46) dominating our sample. This population contains significantly less diversity when compared against the global population of Cng, specifically Africa. Genetic diversity in Cng was significantly subdivided at the continental level with nearly half (47%) of the global STs unique to a genetically diverse and recombining population in Botswana. These patterns of diversity, when combined with evidence from haplotypic networks and coalescent analyses of global populations, are highly suggestive of an expansion of the Cng VNI clade out of Africa, leading to a limited number of genotypes founding the Asian populations. Divergence time testing estimates the time to the most common ancestor between the African and Asian populations to be 6,920 years ago (95% HPD 122.96 - 27,177.76). Further high-density sampling of global Cng STs is now necessary to resolve the temporal sequence underlying the global emergence of this human pathogen. PMID:21573144

The Trehalose Synthesis Pathway Is an Integral Part of the Virulence Composite for Cryptococcus gattii▿ §

PubMed Central

Ngamskulrungroj, Popchai; Himmelreich, Uwe; Breger, Julia A.; Wilson, Christabel; Chayakulkeeree, Methee; Krockenberger, Mark B.; Malik, Richard; Daniel, Heide-Marie; Toffaletti, Dena; Djordjevic, Julianne T.; Mylonakis, Eleftherios; Meyer, Wieland; Perfect, John R.

2009-01-01

The trehalose pathway is essential for stress tolerance and virulence in fungi. We investigated the importance of this pathway for virulence of the pathogenic yeast Cryptococcus gattii using the highly virulent Vancouver Island, Canada, outbreak strain R265. Three genes putatively involved in trehalose biosynthesis, TPS1 (trehalose-6-phosphate [T6P] synthase) and TPS2 (T6P phosphatase), and degradation, NTH1 (neutral trehalose), were deleted in this strain, creating the R265tps1Δ, R265tps2Δ, and R265nth1Δ mutants. As in Cryptococcus neoformans, cellular trehalose was reduced in the R265tps1Δ and R265tps2Δ mutants, which could not grow and died, respectively, at 37°C on yeast extract-peptone-dextrose agar, suggesting that T6P accumulation in R265tps2Δ is directly toxic. Characterizations of the cryptococcal hexokinases and trehalose mutants support their linkage to the control of glycolysis in this species. However, unlike C. neoformans, the C. gattii R265tps1Δ mutant demonstrated, in addition, defects in melanin and capsule production, supporting an influence of T6P on these virulence pathways. Attenuated virulence of the R265tps1Δ mutant was not due solely to its 37°C growth defect, as shown in worm studies and confirmed by suppressor mutants. Furthermore, an intact trehalose pathway controls protein secretion, mating, and cell wall integrity in C. gattii. Thus, the trehalose synthesis pathway plays a central role in the virulence composites of C. gattii through multiple mechanisms. Deletion of NTH1 had no effect on virulence, but inactivation of the synthesis genes, TPS1 and TPS2, has profound effects on survival of C. gattii in the invertebrate and mammalian hosts. These results highlight the central importance of this pathway in the virulence composites of both pathogenic cryptococcal species. PMID:19651856

Low diversity Cryptococcus neoformans variety grubii multilocus sequence types from Thailand are consistent with an ancestral African origin.

PubMed

Simwami, Sitali P; Khayhan, Kantarawee; Henk, Daniel A; Aanensen, David M; Boekhout, Teun; Hagen, Ferry; Brouwer, Annemarie E; Harrison, Thomas S; Donnelly, Christl A; Fisher, Matthew C

2011-04-01

The global burden of HIV-associated cryptococcal meningitis is estimated at nearly one million cases per year, causing up to a third of all AIDS-related deaths. Molecular epidemiology constitutes the main methodology for understanding the factors underpinning the emergence of this understudied, yet increasingly important, group of pathogenic fungi. Cryptococcus species are notable in the degree that virulence differs amongst lineages, and highly-virulent emerging lineages are changing patterns of human disease both temporally and spatially. Cryptococcus neoformans variety grubii (Cng, serotype A) constitutes the most ubiquitous cause of cryptococcal meningitis worldwide, however patterns of molecular diversity are understudied across some regions experiencing significant burdens of disease. We compared 183 clinical and environmental isolates of Cng from one such region, Thailand, Southeast Asia, against a global MLST database of 77 Cng isolates. Population genetic analyses showed that Thailand isolates from 11 provinces were highly homogenous, consisting of the same genetic background (globally known as VNI) and exhibiting only ten nearly identical sequence types (STs), with three (STs 44, 45 and 46) dominating our sample. This population contains significantly less diversity when compared against the global population of Cng, specifically Africa. Genetic diversity in Cng was significantly subdivided at the continental level with nearly half (47%) of the global STs unique to a genetically diverse and recombining population in Botswana. These patterns of diversity, when combined with evidence from haplotypic networks and coalescent analyses of global populations, are highly suggestive of an expansion of the Cng VNI clade out of Africa, leading to a limited number of genotypes founding the Asian populations. Divergence time testing estimates the time to the most common ancestor between the African and Asian populations to be 6,920 years ago (95% HPD 122.96 - 27,177.76). Further high-density sampling of global Cng STs is now necessary to resolve the temporal sequence underlying the global emergence of this human pathogen.

Inhibitory activity of isoniazid and ethionamide against Cryptococcus biofilms.

PubMed

Cordeiro, Rossana de Aguiar; Serpa, Rosana; Marques, Francisca Jakelyne de Farias; de Melo, Charlline Vládia Silva; Evangelista, Antonio José de Jesus; Mota, Valquíria Ferreira; Brilhante, Raimunda Sâmia Nogueira; Bandeira, Tereza de Jesus Pinheiro Gomes; Rocha, Marcos Fábio Gadelha; Sidrim, José Júlio Costa

2015-11-01

In recent years, the search for drugs to treat systemic and opportunistic mycoses has attracted great interest from the scientific community. This study evaluated the in vitro inhibitory effect of the antituberculosis drugs isoniazid and ethionamide alone and combined with itraconazole and fluconazole against biofilms of Cryptococcus neoformans and Cryptococcus gattii. Antimicrobials were tested at defined concentrations after susceptibility assays with Cryptococcus planktonic cells. In addition, we investigated the synergistic interaction of antituberculosis drugs and azole derivatives against Cryptococcus planktonic cells, as well as the influence of isoniazid and ethionamide on ergosterol content and cell membrane permeability. Isoniazid and ethionamide inhibited both biofilm formation and viability of mature biofilms. Combinations formed by antituberculosis drugs and azoles proved synergic against both planktonic and sessile cells, showing an ability to reduce Cryptococcus biofilms by approximately 50%. Furthermore, isoniazid and ethionamide reduced the content of ergosterol in Cryptococcus spp. planktonic cells and destabilized or permeabilized the fungal cell membrane, leading to leakage of macromolecules. Owing to the paucity of drugs able to inhibit Cryptococcus biofilms, we believe that the results presented here might be of interest in the designing of new antifungal compounds.

Effects of radiation type and delivery mode on a radioresistant eukaryote Cryptococcus neoformans

PubMed Central

Shuryak, Igor; Bryan, Ruth A.; Broitman, Jack; Marino, Stephen A.; Morgenstern, Alfred; Apostolidis, Christos; Dadachova, Ekaterina

2015-01-01

Introduction Most research on radioresistant fungi, particularly on human pathogens such as Cryptococcus neoformans, involves sparsely-ionizing radiation. Consequently, fungal responses to densely-ionizing radiation, which can be harnessed to treat life-threatening fungal infections, remain incompletely understood. Methods We addressed this issue by quantifying and comparing the effects of densely-ionizing α-particles (delivered either by external beam or by 213Bi-labeled monoclonal antibodies), and sparsely-ionizing 137Cs γ-rays, on Cryptococus neoformans. Results The best-fit linear-quadratic parameters for clonogenic survival were the following: α=0.24×10−2 Gy−1 for γ-rays and 1.07×10−2 Gy−1 for external-beam α-particles, and β=1.44×10−5 Gy−2 for both radiation types. Fungal cell killing by radiolabeled antibodies was consistent with predictions based on the α-particle dose to the cell nucleus and the linear-quadratic parameters for external-beam α-particles. The estimated RBE (for α-particles vs γ-rays) at low doses was 4.47 for the initial portion of the α-particle track, and 7.66 for the Bragg peak. Non-radiological antibody effects accounted for up to 23% of cell death. Conclusions These results quantify the degree of C. neoformans resistance to densely-ionizing radiations, and show how this resistance can be overcome with fungus-specific radiolabeled antibodies. PMID:25800676

Non-pyogenic infections of the spine.

PubMed

Skaf, Ghassan S; Kanafani, Zeina A; Araj, George F; Kanj, Souha S

2010-08-01

Subacute and chronic spondylodiscitis can be caused by a wide spectrum of infectious aetiologies including Mycobacterium tuberculosis, Brucella spp. and a variety of fungi including Aspergillus spp., Candida spp. and Cryptococcus neoformans. Knowledge of the local epidemiology and prior exposure might suggest the aetiology. Non-invasive diagnostic approaches, such as blood culture or antibody titres in the case of Brucella or antigen detection in the case of fungal infections, can be helpful in reaching the diagnosis. However, direct aspiration or tissue biopsy is usually necessary to identify the causative organism. Specimens are usually sent for pathology, special stains, cultures and, when indicated, molecular analysis. To minimise morbidity and mortality, antibiotic treatment should be initiated promptly directed against the suspected organism, and later adjusted according to the confirmed aetiology. Surgical treatment is reserved for recurrent infection, unstable spinal segment or marked kyphosis in the face of any neurological deficits and uncontrollable pain. Surgical approaches are dictated by the anatomic location of the offending lesion. Once medical treatment fails and surgery becomes warranted, we advocate the use of a two-stage surgical treatment for non-fixed kyphosis and a three-stage operation for fixed kyphosis. Copyright (c) 2010 Elsevier B.V. and the International Society of Chemotherapy. All rights reserved.

Cryptococcus vaughanmartiniae sp. nov. and Cryptococcus onofrii sp. nov.: two new species isolated from worldwide cold environments.

PubMed

Turchetti, Benedetta; Selbmann, Laura; Blanchette, Robert A; Di Mauro, Simone; Marchegiani, Elisabetta; Zucconi, Laura; Arenz, Brett E; Buzzini, Pietro

2015-01-01

Twenty yeast strains, representing a selection from a wider group of more than 60 isolates were isolated from cold environments worldwide (Antarctica, Iceland, Russia, USA, Italian and French Alps, Apennines). The strains were grouped based on their common morphological and physiological characteristics. A phylogeny based on D1/D2 ribosomal DNA sequences placed them in an intermediate position between Cryptococcus saitoi and Cryptococcus friedmannii; the ITS1 and ITS2 rDNA phylogeny demonstrated that these strains belong to two related but hitherto unknown species within the order Filobasidiales, albidus clade. These two novel species are described with the names Cryptococcus vaughanmartiniae (type strain DBVPG 4736(T)) and Cryptococcus onofrii (type strain DBVPG 5303(T)).

An alternative method for the analysis of melanin production in Cryptococcus neoformans sensu lato and Cryptococcus gattii sensu lato.

PubMed

Brilhante, Raimunda S N; España, Jaime D A; de Alencar, Lucas P; Pereira, Vandbergue S; Castelo-Branco, Débora de S C M; Pereira-Neto, Waldemiro de A; Cordeiro, Rossana de A; Sidrim, José J C; Rocha, Marcos F G

2017-10-01

Melanin is an important virulence factor for several microorganisms, including Cryptococcus neoformans sensu lato and Cryptococcus gattii sensu lato, thus, the assessment of melanin production and its quantification may contribute to the understanding of microbial pathogenesis. The objective of this study was to standardise an alternative method for the production and indirect quantification of melanin in C. neoformans sensu lato and C. gattii sensu lato. Eight C. neoformans sensu lato and three C. gattii sensu lato, identified through URA5 methodology, Candida parapsilosis ATCC 22019 (negative control) and one Hortaea werneckii (positive control) were inoculated on minimal medium agar with or without L-DOPA, in duplicate, and incubated at 35°C, for 7 days. Pictures were taken from the third to the seventh day, under standardised conditions in a photographic chamber. Then, photographs were analysed using grayscale images. All Cryptococcus spp. strains produced melanin after growth on minimal medium agar containing L-DOPA. C. parapsilosis ATCC 22019 did not produce melanin on medium containing L-DOPA, while H. werneckii presented the strongest pigmentation. This new method allows the indirect analysis of melanin production through pixel quantification in grayscale images, enabling the study of substances that can modulate melanin production. © 2017 Blackwell Verlag GmbH.

Analysis of sphingolipids, sterols, and phospholipids in human pathogenic Cryptococcus strains.

PubMed

Singh, Ashutosh; MacKenzie, Andrew; Girnun, Geoffrey; Del Poeta, Maurizio

2017-10-01

Cryptococcus species cause invasive infections in humans. Lipids play an important role in the progression of these infections. Independent studies done by our group and others provide some detail about the functions of these lipids in Cryptococcus infections. However, the pathways of biosynthesis and the metabolism of these lipids are not completely understood. To thoroughly understand the physiological role of these Cryptococcus lipids, a proper structure and composition analysis of Cryptococcus lipids is demanded. In this study, a detailed spectroscopic analysis of lipid extracts from Cryptococcus gattii and Cryptococcus grubii strains is presented. Sphingolipid profiling by LC-ESI-MS/MS was used to analyze sphingosine, dihydrosphingosine, sphingosine-1-phosphate, dihydrosphingosine-1-phosphate, ceramide, dihydroceramide, glucosylceramide, phytosphingosine, phytosphingosine-1-phosphate, phytoceramide, α-hydroxy phytoceramide, and inositolphosphorylceramide species. A total of 13 sterol species were identified using GC-MS, where ergosterol is the most abundant species. The 31 P-NMR-based phospholipid analysis identified phosphatidylcholine, phosphatidylethanolamine, phosphatidylinositol, phosphatidylserine, phosphatidyl- N , N -dimethylethanolamine, phosphatidyl- N -monomethylethanolamine, phosphatidylglycerol, phosphatidic acid, and lysophosphatidylethanolamine. A comparison of lipid profiles among different Cryptococcus strains illustrates a marked change in the metabolic flux of these organisms, especially sphingolipid metabolism. These data improve our understanding of the structure, biosynthesis, and metabolism of common lipid groups of Cryptococcus and should be useful while studying their functional significance and designing therapeutic interventions. Copyright © 2017 by the American Society for Biochemistry and Molecular Biology, Inc.

The impact of proteomics on the understanding of functions and biogenesis of fungal extracellular vesicles.

PubMed

Rodrigues, Marcio L; Nakayasu, Ernesto S; Almeida, Igor C; Nimrichter, Leonardo

2014-01-31

Several microbial molecules are released to the extracellular space in vesicle-like structures. In pathogenic fungi, these molecules include pigments, polysaccharides, lipids, and proteins, which traverse the cell wall in vesicles that accumulate in the extracellular space. The diverse composition of fungal extracellular vesicles (EV) is indicative of multiple mechanisms of cellular biogenesis, a hypothesis that was supported by EV proteomic studies in a set of Saccharomyces cerevisiae strains with defects in both conventional and unconventional secretory pathways. In the human pathogens Cryptococcus neoformans, Histoplasma capsulatum, and Paracoccidioides brasiliensis, extracellular vesicle proteomics revealed the presence of proteins with both immunological and pathogenic activities. In fact, fungal EV have been demonstrated to interfere with the activity of immune effector cells and to increase fungal pathogenesis. In this review, we discuss the impact of proteomics on the understanding of functions and biogenesis of fungal EV, as well as the potential role of these structures in fungal pathogenesis. This article is part of a Special Issue entitled: Trends in Microbial Proteomics. Copyright © 2013 Elsevier B.V. All rights reserved.

Antioxidant and Antimycotic Activities of Two Native Lavandula Species from Portugal

PubMed Central

Baptista, Rafael; Madureira, Ana Margarida; Jorge, Rita; Adão, Rita; Duarte, Aida; Duarte, Noélia; Lopes, Maria Manuel; Teixeira, Generosa

2015-01-01

The antioxidant and antimycotic activities of the essential oils and extracts of two native Portuguese Lavandula species, L. stoechas subsp. luisieri and L. pedunculata, were evaluated by in vitro assays. The total phenolics and flavonoids content were also determined. The antioxidant potential was assessed through DPPH radical scavenging, inhibition of lipid peroxidation (ILP), and DNA protection assays. All samples displayed a high DPPH scavenging activity, some of them showing concentration dependence. The majority of the samples were also able to inhibit lipid peroxidation. A strong correlation was observed between the results of DPPH and ILP assays and the flavonoids content of the samples. In the DNA protection assay, all the extracts were able to preserve DNA integrity. The antimycotic activity was performed against twelve fungi belonging to Basidiomycota and Ascomycota Divisions. L. stoechas subsp. luisieri exhibited the broadest activity spectra. L. pedunculata extracts were active against five fungi. Cryptococcus neoformans was the most sensitive, being inhibited by all the extracts. Our results led to the conclusion that L. stoechas subsp. luisieri and L. pedunculata can be useful as new sources of natural antioxidants and antimycotic agents, providing a possible valorization of the existing biodiversity and resources of Portuguese flora. PMID:25922611

Fungal Community Associated with Dactylopius (Hemiptera: Coccoidea: Dactylopiidae) and Its Role in Uric Acid Metabolism

PubMed Central

Vera-Ponce de León, Arturo; Sanchez-Flores, Alejandro; Rosenblueth, Mónica; Martínez-Romero, Esperanza

2016-01-01

We studied fungal species associated with the carmine cochineal Dactylopius coccus and other non-domesticated Dactylopius species using culture-dependent and -independent methods. Thirty seven fungi were isolated in various culture media from insect males and females from different developmental stages and Dactylopius species. 26S rRNA genes and ITS sequences, from cultured fungal isolates revealed different species of Cryptococcus, Rhodotorula, Debaryomyces, Trametes, and Penicillium, which are genera newly associated with Dactylopius. Uric acid (UA) and uricase activity were detected in tissues extracts from different insect developmental stages. However, accumulation of high UA levels and low uricase activities were found only after antifungal treatments, suggesting an important role of fungal species in its metabolism. Additionally, uricolytic fungal isolates were identified and characterized that presumably are involved in nitrogen recycling metabolism. After metagenomic analyses from D. coccus gut and hemolymph DNA and from two published data sets, we confirmed the presence of fungal genes involved in UA catabolism, suggesting that fungi help in the nitrogen recycling process in Dactylopius by uricolysis. All these results show the importance of fungal communities in scale insects such as Dactylopius. PMID:27446001

Rapid Identification of Cryptococcus neoformans and Cryptococcus gattii by Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry ▿

PubMed Central

McTaggart, Lisa R.; Lei, Eric; Richardson, Susan E.; Hoang, Linda; Fothergill, Annette; Zhang, Sean X.

2011-01-01

Compared to DNA sequence analysis, matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS) correctly identified 100% of Cryptococcus species, distinguishing the notable pathogens Cryptococcus neoformans and C. gattii. Identification was greatly enhanced by supplementing a commercial spectral library with additional entries to account for subspecies variability. PMID:21653762

Plants promote mating and dispersal of the human pathogenic fungus Cryptococcus

PubMed Central

Mohan, Rajinikanth; Heitman, Joseph

2017-01-01

Infections due to Cryptococcus are a leading cause of fungal infections worldwide and are acquired as a result of environmental exposure to desiccated yeast or spores. The ability of Cryptococcus to grow, mate, and produce infectious propagules in association with plants is important for the maintenance of the genetic diversity and virulence factors important for infection of animals and humans. In the Western United States and Canada, Cryptococcus has been associated with conifers and tree species other than Eucalyptus; however, to date Cryptococcus has only been studied on live Arabidopsis thaliana, Eucalyptus sp., and Terminalia catappa (almond) seedlings. Previous research has demonstrated the ability of Cryptococcus to colonize live plants, leaves, and vasculature. We investigated the ability of Cryptococcus to grow on live seedlings of the angiosperms, A. thaliana, Eucalyptus camaldulensis, Colophospermum mopane, and the gymnosperms, Pseudotsuga menziesii (Douglas fir), and Tsuga heterophylla (Western hemlock). We observed a broad-range ability of Cryptococcus to colonize both traditional infection models as well as newly tested conifer species. Furthermore, C. neoformans, C. deneoformans, C. gattii (VGI), C. deuterogattii (VGII) and C. bacillisporus (VGIII) were able to colonize live plant leaves and needles but also undergo filamentation and mating on agar seeded with plant materials or in saprobic association with dead plant materials. The ability of Cryptococcus to grow and undergo filamentation and reproduction in saprobic association with both angiosperms and gymnosperms highlights an important role of plant debris in the sexual cycle and exposure to infectious propagules. This study highlights the broad importance of plants (and plant debris) as the ecological niche and reservoirs of infectious propagules of Cryptococcus in the environment. PMID:28212396

Plants promote mating and dispersal of the human pathogenic fungus Cryptococcus.

PubMed

Springer, Deborah J; Mohan, Rajinikanth; Heitman, Joseph

2017-01-01

Infections due to Cryptococcus are a leading cause of fungal infections worldwide and are acquired as a result of environmental exposure to desiccated yeast or spores. The ability of Cryptococcus to grow, mate, and produce infectious propagules in association with plants is important for the maintenance of the genetic diversity and virulence factors important for infection of animals and humans. In the Western United States and Canada, Cryptococcus has been associated with conifers and tree species other than Eucalyptus; however, to date Cryptococcus has only been studied on live Arabidopsis thaliana, Eucalyptus sp., and Terminalia catappa (almond) seedlings. Previous research has demonstrated the ability of Cryptococcus to colonize live plants, leaves, and vasculature. We investigated the ability of Cryptococcus to grow on live seedlings of the angiosperms, A. thaliana, Eucalyptus camaldulensis, Colophospermum mopane, and the gymnosperms, Pseudotsuga menziesii (Douglas fir), and Tsuga heterophylla (Western hemlock). We observed a broad-range ability of Cryptococcus to colonize both traditional infection models as well as newly tested conifer species. Furthermore, C. neoformans, C. deneoformans, C. gattii (VGI), C. deuterogattii (VGII) and C. bacillisporus (VGIII) were able to colonize live plant leaves and needles but also undergo filamentation and mating on agar seeded with plant materials or in saprobic association with dead plant materials. The ability of Cryptococcus to grow and undergo filamentation and reproduction in saprobic association with both angiosperms and gymnosperms highlights an important role of plant debris in the sexual cycle and exposure to infectious propagules. This study highlights the broad importance of plants (and plant debris) as the ecological niche and reservoirs of infectious propagules of Cryptococcus in the environment.

Brain Inositol Is a Novel Stimulator for Promoting Cryptococcus Penetration of the Blood-Brain Barrier

PubMed Central

Wang, Yina; Toffaletti, Dena L.; Eugenin, Eliseo; Perfect, John R.; Kim, Kee Jun; Xue, Chaoyang

2013-01-01

Cryptococcus neoformans is the most common cause of fungal meningitis, with high mortality and morbidity. The reason for the frequent occurrence of Cryptococcus infection in the central nervous system (CNS) is poorly understood. The facts that human and animal brains contain abundant inositol and that Cryptococcus has a sophisticated system for the acquisition of inositol from the environment suggests that host inositol utilization may contribute to the development of cryptococcal meningitis. In this study, we found that inositol plays an important role in Cryptococcus traversal across the blood-brain barrier (BBB) both in an in vitro human BBB model and in in vivo animal models. The capacity of inositol to stimulate BBB crossing was dependent upon fungal inositol transporters, indicated by a 70% reduction in transmigration efficiency in mutant strains lacking two major inositol transporters, Itr1a and Itr3c. Upregulation of genes involved in the inositol catabolic pathway was evident in a microarray analysis following inositol treatment. In addition, inositol increased the production of hyaluronic acid in Cryptococcus cells, which is a ligand known to binding host CD44 receptor for their invasion. These studies suggest an inositol-dependent Cryptococcus traversal of the BBB, and support our hypothesis that utilization of host-derived inositol by Cryptococcus contributes to CNS infection. PMID:23592982

Pho4 Is Essential for Dissemination of Cryptococcus neoformans to the Host Brain by Promoting Phosphate Uptake and Growth at Alkaline pH

PubMed Central

Kaufman-Francis, Keren; Desmarini, Desmarini; Juillard, Pierre G.; Li, Cecilia; Stifter, Sebastian A.; Feng, Carl G.; Sorrell, Tania C.; Grau, Georges E. R.; Bahn, Yong-Sun

2017-01-01

ABSTRACT Phosphate acquisition by fungi is regulated by the phosphate-sensing and acquisition (PHO) signaling pathway. Cryptococcus neoformans disseminates from the lung to the brain and is the commonest cause of fungal meningitis worldwide. To investigate the contribution of PHO signaling to cryptococcal dissemination, we characterized a transcription factor knockout strain (hlh3Δ/pho4Δ) defective in phosphate acquisition. Despite little similarity with other fungal Pho4 proteins, Hlh3/Pho4 functioned like a typical phosphate-responsive transcription factor in phosphate-deprived cryptococci, accumulating in nuclei and triggering expression of genes involved in phosphate acquisition. The pho4Δ mutant strain was susceptible to a number of stresses, the effect of which, except for alkaline pH, was alleviated by phosphate supplementation. Even in the presence of phosphate, the PHO pathway was activated in wild-type cryptococci at or above physiological pH, and under these conditions, the pho4Δ mutant had a growth defect and compromised phosphate uptake. The pho4Δ mutant was hypovirulent in a mouse inhalation model, where dissemination to the brain was reduced dramatically, and markedly hypovirulent in an intravenous dissemination model. The pho4Δ mutant was not detected in blood, nor did it proliferate significantly when cultured with peripheral blood monocytes. In conclusion, dissemination of infection and the pathogenesis of meningitis are dependent on cryptococcal phosphate uptake and stress tolerance at alkaline pH, both of which are Pho4 dependent. IMPORTANCE Cryptococcal meningitis is fatal without treatment and responsible for more than 500,000 deaths annually. To be a successful pathogen, C. neoformans must obtain an adequate supply of essential nutrients, including phosphate, from various host niches. Phosphate acquisition in fungi is regulated by the PHO signaling cascade, which is activated when intracellular phosphate decreases below a critical level. Induction of phosphate acquisition genes leads to the uptake of free phosphate via transporters. By blocking the PHO pathway using a Pho4 transcription factor mutant (pho4Δ mutant), we demonstrate the importance of the pathway for cryptococcal dissemination and the establishment of brain infection in murine models. Specifically, we show that reduced dissemination of the pho4Δ mutant to the brain is due to an alkaline pH tolerance defect, as alkaline pH mimics the conditions of phosphate deprivation. The end result is inhibited proliferation in host tissues, particularly in blood. Podcast: A podcast concerning this article is available. PMID:28144629

An Assessment of Alternative Diesel Fuels: Microbiological Contamination and Corrosion Under Storage Conditions

DTIC Science & Technology

2010-08-01

Sphingomonas" Alphaproteobacteria"’h, Betaproteobacteriah. Sphingomonas"’ Alphaproteobacteriaah. Sphingomonas Paecilomyces A ureohasidium. Cryptococcus ...Paecilomyces A ureohasidium, Cryptococcus . Paecilomyces A ureohasidium Cryptococcus Aureobasiditim" Calosphaeria", Paecilomyces Rhodotorula"x

Research trends on pathogenic Cryptococcus species in the last 20 years: a global analysis with focus on Brazil.

PubMed

Albuquerque, Priscila C; Rodrigues, Marcio L

2012-03-01

Recent data demonstrates that cryptococcosis caused by Cryptococcus neoformans or Cryptococcus gattii kills approximately 600,000 people per year in the world. In Brazil, cryptococcosis has recently been identified as the most fatal mycosis in AIDS patients. In this study, we aimed to map research into C. neoformans and C. gattii in the world, with a focus on the Brazilian contribution to this area. The parameters used for this analysis were based on publication records, including number of articles published, citation indices, journal impact factor and distribution of authorship in the last two decades. Our global analysis of publications demonstrated that, in the last 20 years, the USA was the country that produced the highest number of scientific articles in the Cryptococcus field, while Brazil occupied the third position. Brazilian productivity, however, showed a steady tendency to increase, in contrast to the USA and other countries. The average impact factor of journals at which articles authored by Brazilians were published was 2.58, which represented approximately half the value found for papers of American authorship. Studies authored by Brazilian scientists showed relatively low averages of citations per article, in comparison to papers published by researchers from the USA, France, Australia, The Netherlands and Germany, among others. This study demonstrates that the contribution of Brazilian scientists to the Cryptococcus field is continually growing, although papers produced in Brazil apparently have poor repercussion in comparison to those generated in developed countries.

A multiplex real-time PCR assay for identification of Pneumocystis jirovecii, Histoplasma capsulatum, and Cryptococcus neoformans/Cryptococcus gattii in samples from AIDS patients with opportunistic pneumonia.

PubMed

Gago, Sara; Esteban, Cristina; Valero, Clara; Zaragoza, Oscar; Puig de la Bellacasa, Jorge; Buitrago, María José

2014-04-01

A molecular diagnostic technique based on real-time PCR was developed for the simultaneous detection of three of the most frequent causative agents of fungal opportunistic pneumonia in AIDS patients: Pneumocystis jirovecii, Histoplasma capsulatum, and Cryptococcus neoformans/Cryptococcus gattii. This technique was tested in cultured strains and in clinical samples from HIV-positive patients. The methodology used involved species-specific molecular beacon probes targeted to the internal transcribed spacer regions of the rDNA. An internal control was also included in each assay. The multiplex real-time PCR assay was tested in 24 clinical strains and 43 clinical samples from AIDS patients with proven fungal infection. The technique developed showed high reproducibility (r(2) of >0.98) and specificity (100%). For H. capsulatum and Cryptococcus spp., the detection limits of the method were 20 and 2 fg of genomic DNA/20 μl reaction mixture, respectively, while for P. jirovecii the detection limit was 2.92 log10 copies/20 μl reaction mixture. The sensitivity in vitro was 100% for clinical strains and 90.7% for clinical samples. The assay was positive for 92.5% of the patients. For one of the patients with proven histoplasmosis, P. jirovecii was also detected in a bronchoalveolar lavage sample. No PCR inhibition was detected. This multiplex real-time PCR technique is fast, sensitive, and specific and may have clinical applications.

First report on Cryptococcus neoformans in pigeon excreta from public and residential locations in the metropolitan area of Cuiabá, State of Mato Grosso, Brazil.

PubMed

Takahara, Doracilde Terumi; Lazéra, Márcia dos Santos; Wanke, Bodo; Trilles, Luciana; Dutra, Valéria; Paula, Daphine Ariadne Jesus de; Nakazato, Luciano; Anzai, Mariana Caselli; Leite Júnior, Diniz Pereira; Paula, Claudete Rodrigues; Hahn, Rosane Christine

2013-01-01

Cryptococcosis is a severe systemic mycosis caused by two species of Cryptococcus that affect humans and animals: C. neoformans and C. gattii. Cosmopolitan and emergent, the mycosis results from the interaction between a susceptible host and the environment. The occurrence of C. neoformans was evaluated in 122 samples of dried pigeon excreta collected in 49 locations in the City of Cuiabá, State of Mato Grosso, Brazil, including public squares (n = 5), churches (n = 4), educational institutions (n = 3), health units (n = 8), open areas covered with asbestos (n = 4), residences (n = 23), factory (n = 1) and a prison (n = 1). Samples collected from July to December of 2010 were seeded on Niger seed agar (NSA). Dark brown colonies were identified by urease test, carbon source assimilation tests and canavanine-glycine-bromothymol blue medium. Polymerase chain reaction primer pairs specific for C. neoformans were also used for identification. Cryptococcus neoformans associated to pigeon excreta was isolated from eight (6.6%) samples corresponding to six (12.2%) locations. Cryptococcus neoformans was isolated from urban areas, predominantly in residences, constituting a risk of acquiring the disease by immunocompromised and immunocompetent individuals.

Cutaneous Cryptococcus laurentii infection in an immunocompetent child.

PubMed

Molina-Leyva, Alejandro; Ruiz-Carrascosa, Jose C; Leyva-Garcia, Ana; Husein-Elahmed, Husein

2013-12-01

Cryptococcus laurentii is an extremely rare human pathogen. We report a case of primary cutaneous cryptococcosis caused by Cryptococcus laurentii in an immunocompetent patient, an 8-year-old child with a solitary lesion on the forearm. It was impossible to determine the source of infection and no predisposing factors were found. Oral treatment with fluconazole was totally successful. A review of the literature showed only three cases of cutaneous infection by Cryptococcus laurentii. All of the cases occurred in immunocompromised patients. To the best of our knowledge, this is the first case of Cryptococcus laurentii in an immunocompetent host. Copyright © 2013 International Society for Infectious Diseases. Published by Elsevier Ltd. All rights reserved.

Glutathione may have implications in the design of 3-bromopyruvate treatment protocols for both fungal and algal infections as well as multiple myeloma

PubMed Central

Niedźwiecka, Katarzyna; Augustyniak, Daria; Majkowska-Skrobek, Grażyna; Cal-Bąkowska, Magdalena; Ko, Young H.; Pedersen, Peter L.; Goffeau, Andre

2016-01-01

In different fungal and algal species, the intracellular concentration of reduced glutathione (GSH) correlates closely with their susceptibility to killing by the small molecule alkylating agent 3-bromopyruvate (3BP). Additionally, in the case of Cryptococcus neoformans cells 3BP exhibits a synergistic effect with buthionine sulfoximine (BSO), a known GSH depletion agent. This effect was observed when 3BP and BSO were used together at concentrations respectively of 4-5 and almost 8 times lower than their Minimal Inhibitory Concentration (MIC). Finally, at different concentrations of 3BP (equal to the half-MIC, MIC and double-MIC in a case of fungi, 1 mM and 2.5 mM for microalgae and 25, 50, 100 μM for human multiple myeloma (MM) cells), a significant decrease in GSH concentration is observed inside microorganisms as well as tumor cells. In contrast to the GSH concentration decrease, the presence of 3BP at concentrations corresponding to sub-MIC values or half maximal inhibitory concentration (IC50) clearly results in increasing the expression of genes encoding enzymes involved in the synthesis of GSH in Cryptococcus neoformans and MM cells. Moreover, as shown for the first time in the MM cell model, the drastic decrease in the ATP level and GSH concentration and the increase in the amount of ROS caused by 3BP ultimately results in cell death. PMID:27582536

Requirement and Redundancy of the Src Family Kinases Fyn and Lyn in Perforin-Dependent Killing of Cryptococcus neoformans by NK Cells

PubMed Central

Oykhman, Paul; Timm-McCann, Martina; Xiang, Richard F.; Islam, Anowara; Li, Shu Shun; Stack, Danuta; Huston, Shaunna M.; Ma, Ling Ling

2013-01-01

Natural killer (NK) cells directly recognize and kill fungi, such as the pathogenic fungus Cryptococcus neoformans, via cytolytic mechanisms. However, the precise signaling pathways governing this NK cell microbicidal activity and the implications for fungal recognition are still unknown. Previously, it was reported that NK cell anticryptococcal activity is mediated through a conserved phosphatidylinositol 3-kinase–extracellular signal-regulated kinase 1/2 (PI3K-ERK1/2) pathway. Using YT (a human NK-like cell line) and primary human NK cells, we sought to identify the upstream, receptor-proximal signaling elements that led to fungal cytolysis. We demonstrate that Src family kinases were activated in response to C. neoformans. Furthermore, pharmacologic inhibition with an Src kinase inhibitor blocked C. neoformans-induced downstream activation of PI3K and ERK1/2 and abrogated cryptococcal killing. At the same time, the inhibitor disrupted the polarization of perforin-containing granules toward the NK cell-cryptococcal synapse but had no effect on conjugate formation between the organism and the NK cell. Finally, small interfering RNA (siRNA) double (but not single) knockdown of two Src family kinases, Fyn and Lyn, blocked cryptococcal killing. Together these data demonstrate a mechanism whereby the Src family kinases, Fyn and Lyn, redundantly mediate anticryptococcal activity through the activation of PI3K and ERK1/2, which in turn facilitates killing by inducing the polarization of perforin-containing granules to the NK cell-cryptococcal synapse. PMID:23918783

Illuminating choices for library prep: a comparison of library preparation methods for whole genome sequencing of Cryptococcus neoformans using Illumina HiSeq.

PubMed

Rhodes, Johanna; Beale, Mathew A; Fisher, Matthew C

2014-01-01

The industry of next-generation sequencing is constantly evolving, with novel library preparation methods and new sequencing machines being released by the major sequencing technology companies annually. The Illumina TruSeq v2 library preparation method was the most widely used kit and the market leader; however, it has now been discontinued, and in 2013 was replaced by the TruSeq Nano and TruSeq PCR-free methods, leaving a gap in knowledge regarding which is the most appropriate library preparation method to use. Here, we used isolates from the pathogenic fungi Cryptococcus neoformans var. grubii and sequenced them using the existing TruSeq DNA v2 kit (Illumina), along with two new kits: the TruSeq Nano DNA kit (Illumina) and the NEBNext Ultra DNA kit (New England Biolabs) to provide a comparison. Compared to the original TruSeq DNA v2 kit, both newer kits gave equivalent or better sequencing data, with increased coverage. When comparing the two newer kits, we found little difference in cost and workflow, with the NEBNext Ultra both slightly cheaper and faster than the TruSeq Nano. However, the quality of data generated using the TruSeq Nano DNA kit was superior due to higher coverage at regions of low GC content, and more SNPs identified. Researchers should therefore evaluate their resources and the type of application (and hence data quality) being considered when ultimately deciding on which library prep method to use.

Glutathione may have implications in the design of 3-bromopyruvate treatment protocols for both fungal and algal infections as well as multiple myeloma.

PubMed

Niedźwiecka, Katarzyna; Dyląg, Mariusz; Augustyniak, Daria; Majkowska-Skrobek, Grażyna; Cal-Bąkowska, Magdalena; Ko, Young H; Pedersen, Peter L; Goffeau, Andre; Ułaszewski, Stanisław

2016-10-04

In different fungal and algal species, the intracellular concentration of reduced glutathione (GSH) correlates closely with their susceptibility to killing by the small molecule alkylating agent 3-bromopyruvate (3BP). Additionally, in the case of Cryptococcus neoformans cells 3BP exhibits a synergistic effect with buthionine sulfoximine (BSO), a known GSH depletion agent. This effect was observed when 3BP and BSO were used together at concentrations respectively of 4-5 and almost 8 times lower than their Minimal Inhibitory Concentration (MIC). Finally, at different concentrations of 3BP (equal to the half-MIC, MIC and double-MIC in a case of fungi, 1 mM and 2.5 mM for microalgae and 25, 50, 100 μM for human multiple myeloma (MM) cells), a significant decrease in GSH concentration is observed inside microorganisms as well as tumor cells. In contrast to the GSH concentration decrease, the presence of 3BP at concentrations corresponding to sub-MIC values or half maximal inhibitory concentration (IC50) clearly results in increasing the expression of genes encoding enzymes involved in the synthesis of GSH in Cryptococcus neoformans and MM cells. Moreover, as shown for the first time in the MM cell model, the drastic decrease in the ATP level and GSH concentration and the increase in the amount of ROS caused by 3BP ultimately results in cell death.

Biosynthesized silver and gold nanoparticles are potent antimycotics against opportunistic pathogenic yeasts and dermatophytes.

PubMed

Rónavári, Andrea; Igaz, Nóra; Gopisetty, Mohana Krishna; Szerencsés, Bettina; Kovács, Dávid; Papp, Csaba; Vágvölgyi, Csaba; Boros, Imre Miklós; Kónya, Zoltán; Kiricsi, Mónika; Pfeiffer, Ilona

2018-01-01

Epidemiologic observations indicate that the number of systemic fungal infections has increased significantly during the past decades, however in human mycosis, mainly cutaneous infections predominate, generating major public health concerns and providing much of the impetus for current attempts to develop novel and efficient agents against cutaneous mycosis causing species. Innovative, environmentally benign and economic nanotechnology-based approaches have recently emerged utilizing principally biological sources to produce nano-sized structures with unique antimicrobial properties. In line with this, our aim was to generate silver nanoparticles (AgNPs) and gold nanoparticles (AuNPs) by biological synthesis and to study the effect of the obtained nanoparticles on cutaneous mycosis causing fungi and on human keratinocytes. Cell-free extract of the red yeast Phaffia rhodozyma proved to be suitable for nanoparticle preparation and the generated AgNPs and AuNPs were characterized by transmission electron microscopy, dynamic light scattering and X-ray powder diffraction. Antifungal studies demonstrated that the biosynthesized silver particles were able to inhibit the growth of several opportunistic Candida or Cryptococcus species and were highly potent against filamentous Microsporum and Trichophyton dermatophytes. Among the tested species only Cryptococcus neoformans was susceptible to both AgNPs and AuNPs. Neither AgNPs nor AuNPs exerted toxicity on human keratinocytes. Our results emphasize the therapeutic potential of such biosynthesized nanoparticles, since their biocompatibility to skin cells and their outstanding antifungal performance can be exploited for topical treatment and prophylaxis of superficial cutaneous mycosis.

Unisexual Reproduction Drives Meiotic Recombination and Phenotypic and Karyotypic Plasticity in Cryptococcus neoformans

PubMed Central

Sun, Sheng; Billmyre, R. Blake; Mieczkowski, Piotr A.; Heitman, Joseph

2014-01-01

In fungi, unisexual reproduction, where sexual development is initiated without the presence of two compatible mating type alleles, has been observed in several species that can also undergo traditional bisexual reproduction, including the important human fungal pathogens Cryptococcus neoformans and Candida albicans. While unisexual reproduction has been well characterized qualitatively, detailed quantifications are still lacking for aspects of this process, such as the frequency of recombination during unisexual reproduction, and how this compares with bisexual reproduction. Here, we analyzed meiotic recombination during α-α unisexual and a-α bisexual reproduction of C. neoformans. We found that meiotic recombination operates in a similar fashion during both modes of sexual reproduction. Specifically, we observed that in α-α unisexual reproduction, the numbers of crossovers along the chromosomes during meiosis, recombination frequencies at specific chromosomal regions, as well as meiotic recombination hot and cold spots, are all similar to those observed during a-α bisexual reproduction. The similarity in meiosis is also reflected by the fact that phenotypic segregation among progeny collected from the two modes of sexual reproduction is also similar, with transgressive segregation being observed in both. Additionally, we found diploid meiotic progeny were also produced at similar frequencies in the two modes of sexual reproduction, and transient chromosomal loss and duplication likely occurs frequently and results in aneuploidy and loss of heterozygosity that can span entire chromosomes. Furthermore, in both α-α unisexual and a-α bisexual reproduction, we observed biased allele inheritance in regions on chromosome 4, suggesting the presence of fragile chromosomal regions that might be vulnerable to mitotic recombination. Interestingly, we also observed a crossover event that occurred within the MAT locus during α-α unisexual reproduction. Our results provide definitive evidence that α-α unisexual reproduction is a meiotic process similar to a-α bisexual reproduction. PMID:25503976

Unisexual reproduction drives meiotic recombination and phenotypic and karyotypic plasticity in Cryptococcus neoformans.

PubMed

Sun, Sheng; Billmyre, R Blake; Mieczkowski, Piotr A; Heitman, Joseph

2014-12-01

In fungi, unisexual reproduction, where sexual development is initiated without the presence of two compatible mating type alleles, has been observed in several species that can also undergo traditional bisexual reproduction, including the important human fungal pathogens Cryptococcus neoformans and Candida albicans. While unisexual reproduction has been well characterized qualitatively, detailed quantifications are still lacking for aspects of this process, such as the frequency of recombination during unisexual reproduction, and how this compares with bisexual reproduction. Here, we analyzed meiotic recombination during α-α unisexual and a-α bisexual reproduction of C. neoformans. We found that meiotic recombination operates in a similar fashion during both modes of sexual reproduction. Specifically, we observed that in α-α unisexual reproduction, the numbers of crossovers along the chromosomes during meiosis, recombination frequencies at specific chromosomal regions, as well as meiotic recombination hot and cold spots, are all similar to those observed during a-α bisexual reproduction. The similarity in meiosis is also reflected by the fact that phenotypic segregation among progeny collected from the two modes of sexual reproduction is also similar, with transgressive segregation being observed in both. Additionally, we found diploid meiotic progeny were also produced at similar frequencies in the two modes of sexual reproduction, and transient chromosomal loss and duplication likely occurs frequently and results in aneuploidy and loss of heterozygosity that can span entire chromosomes. Furthermore, in both α-α unisexual and a-α bisexual reproduction, we observed biased allele inheritance in regions on chromosome 4, suggesting the presence of fragile chromosomal regions that might be vulnerable to mitotic recombination. Interestingly, we also observed a crossover event that occurred within the MAT locus during α-α unisexual reproduction. Our results provide definitive evidence that α-α unisexual reproduction is a meiotic process similar to a-α bisexual reproduction.

Spores of the mycorrhizal fungus Glomus mosseae host yeasts that solubilize phosphate and accumulate polyphosphates.

PubMed

Mirabal Alonso, Loreli; Kleiner, Diethelm; Ortega, Eduardo

2008-04-01

The present paper reports the presence of bacteria and yeasts tightly associated with spores of an isolate of Glomus mosseae. Healthy spores were surface disinfected by combining chloramine-T 5%, Tween-40, and cephalexin 2.5 g L(-1) (CTCf). Macerates of these spores were incubated on agar media, microorganisms were isolated, and two yeasts were characterized (EndoGm1, EndoGm11). Both yeasts were able to solubilize low-soluble P sources (Ca and Fe phosphates) and accumulate polyphosphates (polyPs). Sequence analysis of 18S ribosomal deoxyribonucleic acid showed that the yeasts belong to the genera Rhodotorula or Rhodosporidium (EndoGm1) and Cryptococcus (EndoGm11). Results from inoculation experiments showed an effect of the spore-associated yeasts on the root growth of rice, suggesting potential tripartite interactions with mycorrhizal fungi and plants.

Antifungal Activity of Plasmacytoid Dendritic Cells and the Impact of Chronic HIV Infection.

PubMed

Maldonado, Samuel; Fitzgerald-Bocarsly, Patricia

2017-01-01

Due to the effectiveness of combined antiretroviral therapy, people living with HIV can control viral replication and live longer lifespans than ever. However, HIV-positive individuals still face challenges to their health and well-being, including dysregulation of the immune system resulting from years of chronic immune activation, as well as opportunistic infections from pathogenic fungi. This review focuses on one of the key players in HIV immunology, the plasmacytoid dendritic cell (pDC), which links the innate and adaptive immune response and is notable for being the body's most potent producer of type-I interferons (IFNs). During chronic HIV infection, the pDC compartment is greatly dysregulated, experiencing a substantial depletion in number and compromise in function. This immune dysregulation may leave patients further susceptible to opportunistic infections. This is especially important when considering a new role for pDCs currently emerging in the literature: in addition to their role in antiviral immunity, recent studies suggest that pDCs also play an important role in antifungal immunity. Supporting this new role, pDCs express C-type lectin receptors including dectin-1, dectin-2, dectin-3, and mannose receptor, and toll-like receptors-4 and -9 that are involved in recognition, signaling, and response to a wide variety of fungal pathogens, including Aspergillus fumigatus, Cryptococcus neoformans, Candida albicans , and Pneumocystis jirovecii . Accordingly, pDCs have been demonstrated to recognize and respond to certain pathogenic fungi, measured via activation, cytokine production, and fungistatic activity in vitro , while in vivo mouse models indicated a strikingly vital role for pDCs in survival against pulmonary Aspergillus challenge. Here, we discuss the role of the pDC compartment and the dysregulation it undergoes during chronic HIV infection, as well as what is known so far about the role and mechanisms of pDC antifungal activity.

Native trees of the Northeast Argentine: natural hosts of the Cryptococcus neoformans-Cryptococcus gattii species complex.

PubMed

Cattana, Maria Emilia; Sosa, María de Los Ángeles; Fernández, Mariana; Rojas, Florencia; Mangiaterra, Magdalena; Giusiano, Gustavo

2014-01-01

In Argentina, information about epidemiology and environmental distribution of Cryptococcus is scarce. The city of Resistencia borders with Brazil and Paraguay where this fungus is endemic. All these supported the need to investigate the ecology of the genus and the epidemiology of cryptococcosis in this area. The aim was to investigate the presence of species of Cryptococcus neoformans-Cryptococcus gattii complex and their genotypes in trees of the city of Resistencia. One hundred and five trees were sampled by swabbing technique. The isolates were identified using conventional and commercial methods and genotyped by PCR-RFLP (Restriction Fragment Length Polymorphism). Cryptococcus was found in 7 out of the total trees. 6 out of 7 Cryptococcus isolates were identified as C. neoformans and one as C. gattii. C. gattii was isolated from Grevillea robusta. C. neoformans strains were isolated from Tabebuia avellanedae and Peltophorum dubium. Genotyping showed that all C. neoformans belonged to the VNI type and C. gattii belonged to the VGI type. This represents the first study on the ecology of Cryptococcus spp. associated to trees from northeastern Argentina, and the first report describing Grevillea robusta as a host of members of this fungal genus. Another finding is the isolation of C. neoformans from Tabebuia avellanedae and Peltophorum dubium, both tree species native to northeastern Argentina. Copyright © 2012 Revista Iberoamericana de Micología. Published by Elsevier Espana. All rights reserved.

Simvastatin inhibits planktonic cells and biofilms of Candida and Cryptococcus species.

PubMed

Brilhante, Raimunda Sâmia Nogueira; Caetano, Erica Pacheco de; Oliveira, Jonathas Sales; Castelo-Branco, Débora de Souza Collares Maia; Souza, Elizabeth Ribeiro Yokobatake; Alencar, Lucas Pereira de; Cordeiro, Rossana de Aguiar; Bandeira, Tereza de Jesus Pinheiro Gomes; Sidrim, José Júlio Costa; Rocha, Marcos Fábio Gadelha

2015-01-01

The antifungal activity of some statins against different fungal species has been reported. Thus, at the first moment, the in vitro antifungal activity of simvastatin, atorvastatin and pravastatin was tested against Candida spp. and Cryptococcus spp. Then, in a second approach, considering that the best results were obtained for simvastatin, this drug was evaluated in combination with antifungal drugs against planktonic growth and tested against biofilms of Candida spp. and Cryptococcus spp. Drug susceptibility testing was performed using the microdilution broth method, as described by the Clinical and Laboratory Standards Institute. The interaction between simvastatin and antifungals against planktonic cells was analyzed by calculating the fractional inhibitory concentration index. Regarding biofilm susceptibility, simvastatin was tested against growing biofilm and mature biofilm of one strain of each tested yeast species. Simvastatin showed inhibitory effect against Candida spp. and Cryptococcus spp. with minimum inhibitory concentration values ranging from 15.6 to 1000 mg L(-1) and from 62.5 to 1000 mg L(-1), respectively. The combination of simvastatin with itraconazole and fluconazole showed synergism against Candida spp. and Cryptococcus spp., while the combination of simvastatin with amphotericin B was synergistic only against Cryptococcus spp. Concerning the biofilm assays, simvastatin was able to inhibit both growing biofilm and mature biofilm of Candida spp. and Cryptococcus spp. The present study showed that simvastatin inhibits planktonic cells and biofilms of Candida and Cryptococcus species. Copyright © 2015 Elsevier Editora Ltda. All rights reserved.

Rapid presumptive identification of Cryptococcus neoformans by staphylococcal coagglutination.

PubMed Central

Maccani, J E

1981-01-01

A coagglutination reagent was prepared by sensitizing the Cowan I strain of Staphylococcus aureus with rabbit immune globulin directed against Cryptococcus neofromans A15 and absorbed with C. laurentii. This reagent was evaluated for its usefulness in differentiating C. neoformans from other yeast colonies rapidly. Antigen-containing extracts were prepared form Sabouraud dextrose agar cultures of 48 C. neoformans, 33 other Cryptococcus species, 21 Candida, 4 Torulopsis, 3 Saccharomyces, and 2 Rhodotorula strains. This was done by suspending a 0.001-ml loopful of colony growth in 0.5 ml of phenolized saline, mixing for 30 s, and then centrifuging. Equal volumes (50 microliters) of coagglutination reagent and yeast extract were mixed within marked circles on a glass slide and then mechanically rotated at 180 rpm for 8 min. Forty-five of the 48 strains of C. neoformans produced strong (3+ to 4+) agglutination, and 3 strains of serotype C produced weak (1+ to 2+) agglutination with the reagent. Other Cryptococcus species which reacted positively were 4 C. albidus subsp. diffluens, 7 C. albidus subsp. albidus, and 2 C. terreus strains; however, false-positive errors in identification were circumvented by performing a supplemental rapid test for nitrate utilization which differentiated these yeasts from C. neoformans. None of the other yeasts tested (including 14 C. laurentii, 2 C. luteolus, and 2 C. uniguttulatus strains) produced any degree of agglutination with the reagent. A commercial cryptococcal latex agglutination reagent (Crypto-Test, Microbiological Associates, Walkersville, Md.) proved less reliable for identifying C. neoformans yeast colonies because of cross-reactions which occurred with all other species of Cryptococcus tested. PMID:7016909

Targeting the mitochondrial respiratory chain of Cryptococcus through antifungal chemosensitization: a model for control of non-fermentative pathogens

USDA-ARS?s Scientific Manuscript database

Enhanced control of species of Cryptococcus, non-fermentative yeast pathogens, was achieved by chemosensitization through co-application of certain compounds with a conventional antimicrobial drug. The species of Cryptococcus tested showed higher sensitivity to mitochondrial respiratory chain inhibi...

Isolation and purification of antigenic components of Cryptococcus.

PubMed

Wozniak, Karen L; Levitz, Stuart M

2009-01-01

The encapsulated fungal pathogens Cryptococcus neoformans and Cryptococcus gattii are significant agents of life-threatening infections, particularly in persons with suppressed cell-mediated immunity. This chapter provides detailed methodology for the purification of two of the major antigen fractions of C. neoformans: glucuronoxylomannan (GXM) and mannoprotein (MP). GXM is the primary component of the polysaccharide capsule, which is the major cryptococcal virulence factor. In contrast, MPs have been identified as key antigens that stimulate T-cell responses. Purification of GXM and MP should assist investigators studying the antigenic, biochemical, and virulence properties of Cryptococcus species.

Diversity of microflora in the gut and casts of tropical composting earthworms reared on different substrates.

PubMed

Parthasarathi, K; Ranganathan, L S; Anandi, V; Zeyer, Josef

2007-01-01

The diversity of fungi, bacteria, yeast, actinomycetes and protozoa were analysed in the gut and casts of Eudrilus eugeniae, Lampito mauritii, Eisenia fetida and Perionyx excavatus, both qualitatively and quantitatively as influenced by different feed substrates like clay loam soil, cowdung and pressmud. While actinomycetes (Streptomyces albus, S. somaliensis, Nocardia asteroides, N. caviae and Saccharomonosporia) were not digested by any of these species of worms, protozoa (Amoeba proteus, A. terricola, Paramecium trichium, Euglena viridis, E. orientalis, Vorticella picta and Trichomonas hominis) and yeast (Candida tropicalis, C. krusei C. albicans and Cryptococcus neoformans) were totally digested. Certain species of fungi (Saksenae vasiformis, Mucor plumbeus, Cladosporium carrionii, C. herbacium, Alternaria sp., Cunninghamella echinulata, Mycetia sterila, Syncephalostrum racemosum, Curvalaria lunata, C. geniculata and Geotrichum candidum) and bacteria (Pseudomonas aeruginosa, Bacterium antitratum, Mima polymorpha, Enterobacter aerogenes, E. cloacae, Proteus vulgaris, P. mirabilis, P. rettgeri, Escherichia coli, Staphylococus citreus, Bacillus subtilis, B. cereus, Enterococci and Micrococci) were completely digested. Certain other species were not digested fungi like Aspergillus fumigatus, A. flavus, A. ochraceous, Trichoderma koningii (except by Eeugeniae), Fusarium moniliforme (except by E. eugeniae) and Rhizopus sp., and bacteria like Klebsiella pneumoniae and Morganella morganii) and these were multiplied during the transit of the organic residues through the gut of worms. The microbial proliferation was more in the casts, due to the environment prevailing--rich in nutrient supply and large surface area available for growth and reproduction of the microbes that lead to enhanced microbial activity and humic acid contents in the casts.

Genomic Insights into the Atopic Eczema-Associated Skin Commensal Yeast Malassezia sympodialis

PubMed Central

Gioti, Anastasia; Nystedt, Björn; Li, Wenjun; Xu, Jun; Andersson, Anna; Averette, Anna F.; Münch, Karin; Wang, Xuying; Kappauf, Catharine; Kingsbury, Joanne M.; Kraak, Bart; Walker, Louise A.; Johansson, Henrik J.; Holm, Tina; Lehtiö, Janne; Stajich, Jason E.; Mieczkowski, Piotr; Kahmann, Regine; Kennell, John C.; Cardenas, Maria E.; Lundeberg, Joakim; Saunders, Charles W.; Boekhout, Teun; Dawson, Thomas L.; Munro, Carol A.; de Groot, Piet W. J.; Butler, Geraldine; Heitman, Joseph; Scheynius, Annika

2013-01-01

ABSTRACT Malassezia commensal yeasts are associated with a number of skin disorders, such as atopic eczema/dermatitis and dandruff, and they also can cause systemic infections. Here we describe the 7.67-Mbp genome of Malassezia sympodialis, a species associated with atopic eczema, and contrast its genome repertoire with that of Malassezia globosa, associated with dandruff, as well as those of other closely related fungi. Ninety percent of the predicted M. sympodialis protein coding genes were experimentally verified by mass spectrometry at the protein level. We identified a relatively limited number of genes related to lipid biosynthesis, and both species lack the fatty acid synthase gene, in line with the known requirement of these yeasts to assimilate lipids from the host. Malassezia species do not appear to have many cell wall-localized glycosylphosphatidylinositol (GPI) proteins and lack other cell wall proteins previously identified in other fungi. This is surprising given that in other fungi these proteins have been shown to mediate interactions (e.g., adhesion and biofilm formation) with the host. The genome revealed a complex evolutionary history for an allergen of unknown function, Mala s 7, shown to be encoded by a member of an amplified gene family of secreted proteins. Based on genetic and biochemical studies with the basidiomycete human fungal pathogen Cryptococcus neoformans, we characterized the allergen Mala s 6 as the cytoplasmic cyclophilin A. We further present evidence that M. sympodialis may have the capacity to undergo sexual reproduction and present a model for a pseudobipolar mating system that allows limited recombination between two linked MAT loci. PMID:23341551

Exposure to field vs. storage wheat dust: different consequences on respiratory symptoms and immune response among grain workers.

PubMed

Barrera, Coralie; Wild, Pascal; Dorribo, Victor; Savova-Bianchi, Dessislava; Laboissière, Audrey; Pralong, Jacques A; Danuser, Brigitta; Krief, Peggy; Millon, Laurence; Reboux, Gabriel; Niculita-Hirzel, Hélène

2018-05-26

The aim of this study was to understand the differential acute effects of two distinct wheat-related dusts, such as field or stored wheat dust handling, on workers' health and how those effects evolved at 6 month intervals. Exposure, work-related symptoms, changes in lung function, and blood samples of 81 workers handling wheat and 61 controls were collected during the high exposure season and 6 months after. Specific IgG, IgE, and precipitins against 12 fungi isolated from wheat dust were titrated by enzyme-linked immunosorbent assay, dissociation-enhanced lanthanide fluorescence immunoassay, and electrosyneresis. The level of fungi was determined in the workers' environment. Levels of exhaled fraction of nitrogen monoxide (F E NO) and total IgE were obtained. Exposure response associations were investigated by mixed logistic and linear regression models. The recent exposure to field wheat dust was associated with a higher prevalence for five of six self-reported airway symptoms and with a lower F E NO than those in the control population. Exposure to stored wheat dust was only associated with cough. No acute impact of exposure on respiratory function was observed. Exposure to field wheat dust led to workers' sensitization against the three field fungi Aureobasidum, Cryptococcus, and Phoma, although exposure to storage wheat dust was associated with tolerance. The level of Ig remained stable 6 months after exposure. The clinical picture of workers exposed to field or storage wheat dust differed. The systematic characterization of the aerosol microbial profile may help to understand the reasons for those differences.

Metals in fungal virulence

PubMed Central

Gerwien, Franziska; Skrahina, Volha; Kasper, Lydia; Brunke, Sascha

2017-01-01

Abstract Metals are essential for life, and they play a central role in the struggle between infecting microbes and their hosts. In fact, an important aspect of microbial pathogenesis is the ‘nutritional immunity’, in which metals are actively restricted (or, in an extended definition of the term, locally enriched) by the host to hinder microbial growth and virulence. Consequently, fungi have evolved often complex regulatory networks, uptake and detoxification systems for essential metals such as iron, zinc, copper, nickel and manganese. These systems often differ fundamentally from their bacterial counterparts, but even within the fungal pathogens we can find common and unique solutions to maintain metal homeostasis. Thus, we here compare the common and species-specific mechanisms used for different metals among different fungal species—focusing on important human pathogens such as Candida albicans, Aspergillus fumigatus or Cryptococcus neoformans, but also looking at model fungi such as Saccharomyces cerevisiae or A. nidulans as well-studied examples for the underlying principles. These direct comparisons of our current knowledge reveal that we have a good understanding how model fungal pathogens take up iron or zinc, but that much is still to learn about other metals and specific adaptations of individual species—not the least to exploit this knowledge for new antifungal strategies. PMID:29069482

Fungal infections of the spine.

PubMed

Kim, Choll W; Perry, Andrew; Currier, Brad; Yaszemski, Michael; Garfin, Steven R

2006-03-01

Fungal infections of the spine are relatively uncommon. Fungi such as Coccidioides immitis and Blastomyces dermatitidis are limited to specific geographical areas whereas cryptococcus, candida, and aspergillus are found worldwide. Candida and aspergillus are normal commensals of the body and produce disease in susceptible organisms when they gain access to the vascular system through intravenous lines, during implantation of prosthetic devices, or during surgery. For the other fungi, spinal involvement usually is the result of hematogenous or direct spread of organisms from an initial pulmonary source of infection. Involvement of the vertebral bodies can lead to vertebral compression fractures and gross deformity of the spine. Spread of infection along the anterior longitudinal ligament can lead to psoas or paravertebral abscesses. Early recognition of the disease requires a high index of suspicion, proper travel history, and a detailed physical examination. Treatment relies on the prompt institution of appropriate pharmacotherapy and constant monitoring of clinical progress. Resistance to medical therapy, spinal instability, and neurologic deficits are indications for débridement and stabilization with spinal fusion. Prognosis depends on the premorbid state of the patient, the type of fungal organism, and the timing of treatment. Level V (expert opinion). Please see the Guidelines for Authors for a complete description of levels of evidence.

Importance of resolving fungal nomenclature: the case of multiple pathogenic species in the Cryptococcus genus

USDA-ARS?s Scientific Manuscript database

Cryptococcosis is a major fungal disease caused by members of the Cryptococcus gattii and Cryptococcus neoformans species complexes. After more than 15 years of molecular genetic and phenotypic studies and much debate, a proposal for a taxonomic revision was made. The two varieties within C. neoform...

Isolation and Purification of Antigenic Components of Cryptococcus

PubMed Central

Wozniak, Karen L.; Levitz, Stuart M.

2012-01-01

The encapsulated fungal pathogens Cryptococcus neoformans and Cryptococcus gattii are significant agents of life-threatening infections, particularly in persons with suppressed cell-mediated immunity. This chapter provides detailed methodology for the purification of two of the major antigen fractions of C. neoformans: glucuronoxylomannan (GXM) and mannoprotein (MP). GXM is the primary component of the polysaccharide capsule, which is the major cryptococcal virulence factor. In contrast, MPs have been identified as key antigens that stimulate T-cell responses. Purification of GXM and MP should assist investigators studying the antigenic, biochemical, and virulence properties of Cryptococcus species. PMID:19089377

Adaptive Immunity to Cryptococcus neoformans Infections

PubMed Central

Mukaremera, Liliane; Nielsen, Kirsten

2017-01-01

The Cryptococcus neoformans/Cryptococcus gattii species complex is a group of fungal pathogens with different phenotypic and genotypic diversity that cause disease in immunocompromised patients as well as in healthy individuals. The immune response resulting from the interaction between Cryptococcus and the host immune system is a key determinant of the disease outcome. The species C. neoformans causes the majority of human infections, and therefore almost all immunological studies focused on C. neoformans infections. Thus, this review presents current understanding on the role of adaptive immunity during C. neoformans infections both in humans and in animal models of disease. PMID:29333430

Induction of Broad-Spectrum Protective Immunity against Disparate Cryptococcus Serotypes

PubMed Central

Van Dyke, Marley C. Caballero; Chaturvedi, Ashok K.; Hardison, Sarah E.; Leopold Wager, Chrissy M.; Castro-Lopez, Natalia; Hole, Camaron R.; Wozniak, Karen L.; Wormley, Floyd L.

2017-01-01

Cryptococcosis is a fungal disease caused by multiple Cryptococcus serotypes; particularly C. neoformans (serotypes A and D) and C. gattii (serotypes B and C). To date, there is no clinically available vaccine to prevent cryptococcosis. Mice given an experimental pulmonary vaccination with a C. neoformans serotype A strain engineered to produce interferon-γ, denoted H99γ, are protected against a subsequent otherwise lethal experimental infection with C. neoformans serotype A. Thus, we determined the efficacy of immunization with C. neoformans strain H99γ to elicit broad-spectrum protection in BALB/c mice against multiple disparate Cryptococcus serotypes. We observed significantly increased survival rates and significantly decreased pulmonary fungal burden in H99γ immunized mice challenged with Cryptococcus serotypes A, B, or D compared to heat-killed H99γ (HKH99γ) immunized mice. Results indicated that prolonged protection against Cryptococcus serotypes B or D in H99γ immunized mice was CD4+ T cell dependent and associated with the induction of predominantly Th1-type cytokine responses. Interestingly, immunization with H99γ did not elicit greater protection against challenge with the Cryptococcus serotype C tested either due to low overall virulence of this strain or enhanced capacity of this strain to evade host immunity. Altogether, these studies provide “proof-of-concept” for the development of a cryptococcal vaccine that provides cross-protection against multiple disparate serotypes of Cryptococcus. PMID:29163469

Fluidized-Bed Drying and Storage Stability of Cryptococcus flavescens OH 182.9, a Biocontrol Agent of Fusarium Head Blight

USDA-ARS?s Scientific Manuscript database

A method to produce dried granules of Cryptococcus flavescens (formerly Cryptococcus nodaensis) OH 182.9 was developed and the granules evaluated for storage stability. Small spherical granules were produced and dried using a fluidized bed dryer. A drying and survival curve was produced for the pr...

Molecular identity and prevalence of Cryptococcus spp. nasal carriage in asymptomatic feral cats in Italy.

PubMed

Danesi, Patrizia; Furnari, Carmelo; Granato, Anna; Schivo, Alice; Otranto, Domenico; Capelli, Gioia; Cafarchia, Claudia

2014-10-01

Cryptococcosis is a life-threatening fungal disease that infects humans and animals worldwide. Inhalation of fungal particles from an environmental source can cause primary infection of the respiratory system. As animals can be considered a sentinel for human diseases, the aim of this study was to determine the prevalence and molecular identity of Cryptococcus spp. in the nasal cavity of feral cats. Cats from 162 urban and rural feral cat colonies were sampled over 3 years. Of 766 cats from which nasal swabs were obtained, Cryptococcus spp. were recovered from 95 (12.6%), including 37 C. magnus (4.8%), 16 C. albidus (2.0%), 15 C. carnescens (1.9%), 12 C. neoformans (1.6%), as well as C. oeirensis (n = 3), C. victoriae (n = 3), C. albidosimilis (n = 2), Filobasidium globisporum (n = 2), C. adeliensis (n = 1), C. flavescens (n = 1), C. dimnae (n = 1), C. saitoi (n = 1), and C. wieringae (n = 1) with prevalence <1%. Thirteen Cryptococcus species were identified by polymerase chain reaction and sequencing of internal transcribed spacer amplicons. Statistical analysis did not identify any predisposing factors that contributed to nasal colonization (eg, sex, age, season, or habitat). Results suggest that asymptomatic feral cats may carry C. neoformans and other Cryptococcus species in their sinonasal cavity. Genotyping of the specific cryptococcal isolates provides a better understanding of the epidemiology of these yeasts. © The Author 2014. Published by Oxford University Press on behalf of The International Society for Human and Animal Mycology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

An Acidic Microenvironment Increases NK Cell Killing of Cryptococcus neoformans and Cryptococcus gattii by Enhancing Perforin Degranulation

PubMed Central

Islam, Anowara; Li, Shu Shun; Oykhman, Paul; Timm-McCann, Martina; Huston, Shaunna M.; Stack, Danuta; Xiang, Richard F.; Kelly, Margaret M.; Mody, Christopher H.

2013-01-01

Cryptococcus gattii and Cryptococcus neoformans are encapsulated yeasts that can produce a solid tumor-like mass or cryptococcoma. Analogous to malignant tumors, the microenvironment deep within a cryptococcoma is acidic, which presents unique challenges to host defense. Analogous to malignant cells, NK cells kill Cryptococcus. Thus, as in tumor defense, NK cells must kill yeast cells across a gradient from physiologic pH to less than 6 in the center of the cryptococcoma. As acidic pH inhibits anti-tumor activities of NK cells, we sought to determine if there was a similar reduction in the anticryptococcal activity of NK cells. Surprisingly, we found that both primary human NK cells and the human NK cell line, YT, have preserved or even enhanced killing of Cryptococcus in acidic, compared to physiological, pH. Studies to explore the mechanism of enhanced killing revealed that acidic pH does not increase the effector to target ratio, binding of cytolytic cells to Cryptococcus, or the active perforin content in effector cells. By contrast, perforin degranulation was greater at acidic pH, and increased degranulation was preceded by enhanced ERK1/2 phosphorylation, which is essential for killing. Moreover, using a replication defective ras1 knockout strain of Cryptococcus increased degranulation occurred during more rapid replication of the organisms. Finally, NK cells were found intimately associated with C. gattii within the cryptococcoma of a fatal infection. These results suggest that NK cells have amplified signaling, degranulation, and greater killing at low pH and when the organisms are replicating quickly, which would help maintain microbicidal host defense despite an acidic microenvironment. PMID:23853583

Diversity and antifungal activity of the endophytic fungi associated with the native medicinal cactus Opuntia humifusa (Cactaceae) from the United States.

PubMed

Silva-Hughes, Alice F; Wedge, David E; Cantrell, Charles L; Carvalho, Camila R; Pan, Zhiqiang; Moraes, Rita M; Madoxx, Victor L; Rosa, Luiz H

2015-06-01

The endophytic fungal community associated with the native cactus Opuntia humifusa in the United States was investigated and its potential for providing antifungal compounds. A hundred-eight endophytic fungal isolates were obtained and identified by molecular methods into 17 different taxa of the genera Alternaria, Aureobasidium, Biscogniauxia, Cladosporium, Cryptococcus, Curvularia, Diaporthe, Epicoccum, Paraconiothyrium, Pestalotiopsis and Phoma. The most frequent species associated with O. humifusa were Alternaria sp. 3, Aureobasidium pullulans and Diaporthe sp. The fungal community of O. humifusa had a high richness and diversity; additionally, the species richness obtained indicates that the sample effort was enough to recover the diversity pattern obtained. Six extracts of endophytes showed antifungal properties and (1)H NMR analyses of the extracts of Alternaria sp. 5 Ohu 8B2, Alternaria sp. 3 Ohu 30A, Cladosporium funiculosum Ohu 17C1 and Paraconiothyrium sp. Ohu 17A indicated the presence of functional groups associated with unsaturated fatty-acid olefinic protons and fatty acid methylene and methyl protons. GC-FID analysis of these extracts confirmed the presence of a mixture of different fatty acids. The (1)H NMR analyses of Biscogniauxia mediterranea Ohu 19B extracts showed the presence of aromatic compounds. From the extract of B. mediterranea we isolated the compound 5-methylmellein that displayed moderate antifungal activity against the phytopathogenic fungi Phomopsis obscurans. Our results suggest that native medicinal cacti of the United States can live symbiotically with rich and diverse endophytic communities and may be a source of bioactive molecules, including those able to inhibit or control plant disease pathogens. Copyright © 2015 Elsevier GmbH. All rights reserved.

Inhibition of the calcineurin pathway by two tannins, chebulagic acid and chebulanin, isolated from Harrisonia abyssinica Oliv.

PubMed

Lee, Won Jeong; Moon, Jae Sun; Kim, Sung In; Kim, Young Tae; Nash, Oyekanmi; Bahn, Yong-Sun; Kim, Sung Uk

2014-10-01

In order to discover and develop novel signaling inhibitors from plants, a screening system was established targeting the two-component system of Cryptococcus neoformans by using the wild type and a calcineurin mutant of C. neoformans, based on the counter-regulatory action of high-osmolarity glycerol (Hog1) mitogen-activated protein kinase and the calcineurin pathways in C. neoformans. Among 10,000 plant extracts, that from Harrisonia abyssinica Oliv. exhibited the most potent inhibitory activity against C. neoformans var. grubii H99 with fludioxonil. Bioassay-guided fractionation was used to isolate two bioactive compounds from H. abyssinica, and these compounds were identified as chebulagic acid and chebulanin using spectroscopic methods. These compounds specifically inhibited the calcineurin pathway in C. neoformans. Moreover, they exhibited potent antifungal activities against various human pathogenic fungi with minimum inhibitory concentrations ranging from 0.25 to over 64 µg/ml.

The influence of Aster x salignus Willd. Invasion on the diversity of soil yeast communities

NASA Astrophysics Data System (ADS)

Glushakova, A. M.; Kachalkin, A. V.; Chernov, I. Yu.

2016-07-01

The annual dynamics of yeast communities were studied in the soddy-podzolic soil under the thickets of Aster x salignus Willd., one of the widespread invasive plant species in central Russia. Yeast groups in the soils under continuous aster thickets were found to differ greatly from the yeast communities in the soils under the adjacent indigenous meadow vegetation. In both biotopes the same species ( Candida vartiovaarae, Candida sake, and Cryptococcus terreus) are dominants. However, in the soils under indigenous grasses, eurybiontic yeasts Rhodotorula mucilaginosa, which almost never occur in the soil under aster, are widespread. In the soil under aster, the shares of other typical epiphytic and pedobiontic yeast fungi (ascomycetic species Wickerhamomyces aniomalus, Barnettozyma californica and basidiomycetic species Cystofilobasidium macerans, Guehomyces pullulans) significantly increase. Thus, the invasion of Aster x salignus has a clear effect on soil yeast complexes reducing their taxonomic and ecological diversity.

ANTIOXIDANT AND ANTIFUNGAL ACTIVITY OF SELECTED MEDICINAL PLANT EXTRACTS AGAINST PHYTOPATHOGENIC FUNGI

PubMed Central

Mahlo, Salome Mamokone; Chauke, Hasani Richard; McGaw, Lyndy; Eloff, Jacobus

2016-01-01

Background: Medicinal plants are used by many ethnic groups as a source of medicine for the treatment of various ailments in both humans and domestic animals. These plants produce secondary metabolites that have antimicrobial properties, thus screening of medicinal plants provide another alternative for producing chemical fungicides that are relatively non-toxic and cost-effective. Materials and methods: Leaf extracts of selected South African plant species (Bucida buceras, Breonadia salicina, Harpephyllum caffrum, Olinia ventosa, Vangueria infausta and Xylotheca kraussiana) were investigated for activity against selected phytopathogenic fungi (Aspergillus niger, Aspergillus parasiticus, Colletotricum gloeosporioides, Penicillium janthinellum, P. expansum, Trichoderma harzianum and Fusarium oxysporum). These plant fungal pathogens causes major economic losses in fruit industry such as blue rot on nectaries and postharvest disease in citrus. Plant species were selected from 600 evaluated inter alia, against two animal fungal pathogens (Candida albicans and Cryptococcus neoformans). Antioxidant activity of the selected plant extracts were investigated using a qualitative assay (2, 2-diphenyl-1-picrylhydrazyl (DPPH)). Bioautography assay was used to determine the number of antifungal compounds in plant extracts. Results: All plant extracts were active against the selected plant phytopathogenic fungi. Moreover, Bucida buceras had the best antifungal activity against four of the fungi, with minimum inhibitory concentration (MIC) values as low as 0.02 mg/ml and 0.08 mg/ml against P. expansum, P. janthinellum, T. harzianum and F. oxysporum. The plant extracts of five plant species did not possess strong antioxidant activity. However, methanol extract of X. kraussiana was the most active radical scavenger in the DPPH assay amongst the six medicinal plants screened. No antifungal compounds were observed in some of the plant extracts with good antifungal activity as shown in the microdilution assay, indicating possible synergism between the separated metabolites. Conclusion: The results showed that acetone was the best extractant. Furthermore, our findings also confirm the traditional use of Breonadia salicina and demonstrate the potential value of developing biopesticides from plants. PMID:28852739

ANTIOXIDANT AND ANTIFUNGAL ACTIVITY OF SELECTED MEDICINAL PLANT EXTRACTS AGAINST PHYTOPATHOGENIC FUNGI.

PubMed

Mahlo, Salome Mamokone; Chauke, Hasani Richard; McGaw, Lyndy; Eloff, Jacobus

2016-01-01

Medicinal plants are used by many ethnic groups as a source of medicine for the treatment of various ailments in both humans and domestic animals. These plants produce secondary metabolites that have antimicrobial properties, thus screening of medicinal plants provide another alternative for producing chemical fungicides that are relatively non-toxic and cost-effective. Leaf extracts of selected South African plant species ( Bucida buceras, Breonadia salicina, Harpephyllum caffrum, Olinia ventosa, Vangueria infausta and Xylotheca kraussiana ) were investigated for activity against selected phytopathogenic fungi ( Aspergillus niger, Aspergillus parasiticus, Colletotricum gloeosporioides, Penicillium janthinellum, P. expansum, Trichoderma harzianum and Fusarium oxysporum ). These plant fungal pathogens causes major economic losses in fruit industry such as blue rot on nectaries and postharvest disease in citrus. Plant species were selected from 600 evaluated inter alia, against two animal fungal pathogens ( Candida albicans and Cryptococcus neoformans ). Antioxidant activity of the selected plant extracts were investigated using a qualitative assay (2, 2-diphenyl-1-picrylhydrazyl (DPPH)). Bioautography assay was used to determine the number of antifungal compounds in plant extracts. All plant extracts were active against the selected plant phytopathogenic fungi. Moreover, Bucida buceras had the best antifungal activity against four of the fungi, with minimum inhibitory concentration (MIC) values as low as 0.02 mg/ml and 0.08 mg/ml against P. expansum, P. janthinellum, T. harzianum and F. oxysporum . The plant extracts of five plant species did not possess strong antioxidant activity. However, methanol extract of X. kraussiana was the most active radical scavenger in the DPPH assay amongst the six medicinal plants screened. No antifungal compounds were observed in some of the plant extracts with good antifungal activity as shown in the microdilution assay, indicating possible synergism between the separated metabolites. The results showed that acetone was the best extractant. Furthermore, our findings also confirm the traditional use of Breonadia salicina and demonstrate the potential value of developing biopesticides from plants.

Analysis of the Surface Properties of Wheat Spikelet Components and Their Role in Colonization by the Biocontrol Antagonist Cryptococcus flavescens OH 182.9

USDA-ARS?s Scientific Manuscript database

Cryptococcus flavescens OH 182.9 (NRRL Y-30216) is a biocontrol antagonist which has been shown to be effective in managing Fusarium head blight in wheat. Cryptococcus flavescens works by colonizing the wheat spikelet and competing with potential pathogens for the limited resources available. Know...

Cryptococcus fildesensis sp. nov., a psychrophilic basidiomycetous yeast isolated from Antarctic moss.

PubMed

Zhang, Tao; Zhang, Yu-Qin; Liu, Hong-Yu; Su, Jing; Zhao, Li-Xun; Yu, Li-Yan

2014-02-01

Two yeast strains isolated from the moss Chorisodontium aciphyllum from the Fildes Region, King George Island, maritime Antarctica, were classified as members of the genus Cryptococcus based on sequence analyses of the D1/D2 domains of the large subunit rRNA gene and the internal transcribed spacer (ITS) regions. The rRNA gene sequence analyses indicated that the two strains represented a novel species of the genus Cryptococcus, for which the name Cryptococcus fildesensis sp. nov. is proposed (type strain: CPCC 300017(T) = DSM 26442(T) = CBS 12705(T)). The MycoBank number of the novel species is MB 805542.

Comparison of laccase production levels in Pichia pastoris and Cryptococcus sp. S-2.

PubMed

Nishibori, Nahoko; Masaki, Kazuo; Tsuchioka, Hiroaki; Fujii, Tsutomu; Iefuji, Haruyuki

2013-04-01

The heterologous expression of the laccase gene from Trametes versicolor and Gaeumannomyces graminis was evaluated in the yeasts Pichia pastoris and Cryptococcus sp. S-2. The expression levels of both laccase genes in Cryptococcus sp. S-2 were considerably higher than those in P. pastoris. The codon usage of Cryptococcus sp. S-2 as well as the GC content were similar to those of T. versicolor and G. graminis. These results suggest that using a host with a similar codon usage for the expressed gene may improve protein expression. The use of Cryptococcus sp. S-2 as a host may be advantageous for the heterologous expression of genes with high GC content. Moreover, this yeast provides the same advantages as P. pastoris for the production of recombinant proteins, such as growth on minimal medium, capacity for high-density growth during fermentation, and capability for post-translational modifications. Therefore, we propose that Cryptococcus sp. S-2 be used as an expression host to improve enzyme production levels when other hosts have not yielded good results. Copyright © 2012 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Global Molecular Epidemiology of Cryptococcus neoformans and Cryptococcus gattii: An Atlas of the Molecular Types

PubMed Central

Cogliati, Massimo

2013-01-01

Cryptococcosis is a fungal disease affecting more than one million people per year worldwide. The main etiological agents of cryptococcosis are the two sibling species Cryptococcus neoformans and Cryptococcus gattii that present numerous differences in geographical distribution, ecological niches, epidemiology, pathobiology, clinical presentation and molecular characters. Genotyping of the two Cryptococcus species at subspecies level supplies relevant information to understand how this fungus has spread worldwide, the nature of its population structure, and how it evolved to be a deadly pathogen. At present, nine major molecular types have been recognized: VNI, VNII, VNB, VNIII, and VNIV among C. neoformans isolates, and VGI, VGII, VGIII, and VGIV among C. gattii isolates. In this paper all the information available in the literature concerning the isolation of the two Cryptococcus species has been collected and analyzed on the basis of their geographical origin, source of isolation, level of identification, species, and molecular type. A detailed analysis of the geographical distribution of the major molecular types in each continent has been described and represented on thematic maps. This study represents a useful tool to start new epidemiological surveys on the basis of the present knowledge. PMID:24278784

Peeling the onion: the outer layers of Cryptococcus neoformans.

PubMed

Agustinho, Daniel P; Miller, Liza C; Li, Lucy X; Doering, Tamara L

2018-01-01

Cryptococcus neoformans is an opportunistic fungal pathogen that is ubiquitous in the environment. It causes a deadly meningitis that is responsible for over 180,000 deaths worldwide each year, including 15% of all AIDS-related deaths. The high mortality rates for this infection, even with treatment, suggest a need for improved therapy. Unique characteristics of C. neoformans may suggest directions for drug discovery. These include features of three structures that surround the cell: the plasma membrane, the cell wall around it, and the outermost polysaccharide capsule. We review current knowledge of the fundamental biology of these fascinating structures and highlight open questions in the field, with the goal of stimulating further investigation that will advance basic knowledge and human health.

Peeling the onion: the outer layers of Cryptococcus neoformans

PubMed Central

Agustinho, Daniel P; Miller, Liza C; Li, Lucy X; Doering, Tamara L

2018-01-01

Cryptococcus neoformans is an opportunistic fungal pathogen that is ubiquitous in the environment. It causes a deadly meningitis that is responsible for over 180,000 deaths worldwide each year, including 15% of all AIDS-related deaths. The high mortality rates for this infection, even with treatment, suggest a need for improved therapy. Unique characteristics of C. neoformans may suggest directions for drug discovery. These include features of three structures that surround the cell: the plasma membrane, the cell wall around it, and the outermost polysaccharide capsule. We review current knowledge of the fundamental biology of these fascinating structures and highlight open questions in the field, with the goal of stimulating further investigation that will advance basic knowledge and human health. PMID:29742198

Morphologic mimickers of Cryptococcus occurring within inflammatory infiltrates in the setting of neutrophilic dermatitis: a series of three cases highlighting clinical dilemmas associated with a novel histopathologic pitfall.

PubMed

Ko, Jennifer S; Fernandez, Anthony P; Anderson, Kyle A; Burdick, Laura M; Billings, Steven D; Procop, Gary W; McMahon, James T; Bergfeld, Wilma F; Piliang, Melissa P

2013-01-01

A neutrophil-predominant inflammatory infiltrate in a cutaneous biopsy can be associated with a broad spectrum of diseases. Here we describe three cases showing a neutrophil-predominant dermal infiltrate admixed with abundant acellular bodies surrounded by capsule-like vacuolated spaces, which strikingly mimicked Cryptococcus. Two cases occurred within the settings of underlying hematologic malignancies; the third case was associated with immune dysregulation. Two patients were acutely ill in the medical intensive care unit. Fungal work-up, including cultures and multiple stains were negative. Because of clinical deterioration in these patients, transmission electron microscopy was pursued to definitively rule out fungal infection. In both cases, characteristics most compatible with autolysing human cells, not Cryptococcus, were identified. Chemotherapy and high-dose steroids were given, but both patients eventually succumbed to their diseases. To the best of our knowledge, these represent the first reported cases of autolysing human cells mimicking Cryptococcus organisms within neutrophilic infiltrates. They highlight the therapeutic dilemmas arising with histopathologic mimics, as well as the importance of thorough investigation to distinguish mimickers from true infectious organisms. We believe recognition of this microscopic pitfall will be useful to dermatopathologists faced with similar findings in the future, and may prevent unnecessary delay of appropriate therapy in acutely ill patients. Copyright © 2012 John Wiley & Sons A/S.

USSR Report, Life Sciences Biomedical and Behavioral Sciences.

DTIC Science & Technology

1987-03-10

VIRUSOLOGII, No 6, Nov-Dec 85) 13 Possibility of Utilizing Cryptococcus and Lipomyces Yeast for Production of Glucuron-Containing Polysaccharide (I.F...9 Western. 6508/9716 CSO: 1840/176 UDC 547.458:576.8:663.1:576.343 POSSIBILITY OF UTILIZING CRYPTOCOCCUS AND LIPOMYCES YEAST FOR PRODUCTION OF...glucuronic acid, which also has therapeutic properties. The hetero- polysaccharides of yeasts of the genera Cryptococcus and Lipomyces contain 20% or

Treatment of Experimental Anthrax with Recombinant Capsule Depolymerase

DTIC Science & Technology

2007-12-01

infected with Cryptococcus neoformans (15), and the recent work of Mushtaq et al. demonstrated that a capsule-degrading endosialidase could be used to...treatment to remove microbial capsules has been suc- cessfully used to treat existing infections with pneumococci, Cryptococcus , and E. coli (2, 15, 31) in...macrophage sensitivity and resistance to anthrax lethal toxin. Infect. Immun. 61:245–252. 15. Gadebusch, H. H. 1960. Specific degradation of Cryptococcus

Acidotolerant Bacteria and Fungi as a Sink of Methanol-Derived Carbon in a Deciduous Forest Soil

PubMed Central

Morawe, Mareen; Hoeke, Henrike; Wissenbach, Dirk K.; Lentendu, Guillaume; Wubet, Tesfaye; Kröber, Eileen; Kolb, Steffen

2017-01-01

Methanol is an abundant atmospheric volatile organic compound that is released from both living and decaying plant material. In forest and other aerated soils, methanol can be consumed by methanol-utilizing microorganisms that constitute a known terrestrial sink. However, the environmental factors that drive the biodiversity of such methanol-utilizers have been hardly resolved. Soil-derived isolates of methanol-utilizers can also often assimilate multicarbon compounds as alternative substrates. Here, we conducted a comparative DNA stable isotope probing experiment under methylotrophic (only [13C1]-methanol was supplemented) and combined substrate conditions ([12C1]-methanol and alternative multi-carbon [13Cu]-substrates were simultaneously supplemented) to (i) identify methanol-utilizing microorganisms of a deciduous forest soil (European beech dominated temperate forest in Germany), (ii) assess their substrate range in the soil environment, and (iii) evaluate their trophic links to other soil microorganisms. The applied multi-carbon substrates represented typical intermediates of organic matter degradation, such as acetate, plant-derived sugars (xylose and glucose), and a lignin-derived aromatic compound (vanillic acid). An experimentally induced pH shift was associated with substantial changes of the diversity of active methanol-utilizers suggesting that soil pH was a niche-defining factor of these microorganisms. The main bacterial methanol-utilizers were members of the Beijerinckiaceae (Bacteria) that played a central role in a detected methanol-based food web. A clear preference for methanol or multi-carbon substrates as carbon source of different Beijerinckiaceae-affiliated phylotypes was observed suggesting a restricted substrate range of the methylotrophic representatives. Apart from Bacteria, we also identified the yeasts Cryptococcus and Trichosporon as methanol-derived carbon-utilizing fungi suggesting that further research is needed to exclude or prove methylotrophy of these fungi. PMID:28790984

Comparison of biotyping methods as alternative identification tools to molecular typing of pathogenic Cryptococcus species in sub-Saharan Africa

PubMed Central

Nyazika, Tinashe K.; Robertson, Valerie J.; Nherera, Brenda; Mapondera, Prichard T.; Meis, Jacques F.; Hagen, Ferry

2015-01-01

Summary Cryptococcal meningitis is the leading fungal infection and AIDS defining opportunistic illness in patients with late stage HIV infection, particularly in South-East Asia and sub-Saharan Africa. Given the high mortality, clinical differences and the extensive ecological niche of Cryptococcus neoformans and Cryptococcus gattii species complexes, there is need for laboratories in sub-Sahara African countries to adopt new and alternative reliable diagnostic algorithms that rapidly identify and distinguish these species. We biotyped 74 and then amplified fragment length polymorphism (AFLP) genotyped 66 Cryptococcus isolates from a cohort of patients with HIV-associated cryptococcal meningitis. Cryptococcus gattii sensu lato was isolated at a prevalence of 16.7% (n = 11/66) and C. neoformans sensu stricto was responsible for 83.3% (n = 55/66) of the infections. l-Canavanine glycine bromothymol blue, yeast-carbon-base-d-proline-d-tryptophan and creatinine dextrose bromothymol blue thymine were able to distinguish pathogenic C. gattii sensu lato from C. neoformans sensu stricto species when compared with amplified fragment length polymorphism genotyping. This study demonstrates high C. gattii sensu lato prevalence in Zimbabwe. In addition, biotyping methods can be used as alternative diagnostic tools to molecular typing in resource-limited areas for differentiating pathogenic Cryptococcus species. PMID:26661484

Environmental distribution of Cryptococcus neoformans and C. gattii around the Mediterranean basin.

PubMed

Cogliati, Massimo; D'Amicis, Roberta; Zani, Alberto; Montagna, Maria Teresa; Caggiano, Giuseppina; De Giglio, Osvalda; Balbino, Stella; De Donno, Antonella; Serio, Francesca; Susever, Serdar; Ergin, Cagri; Velegraki, Aristea; Ellabib, Mohamed S; Nardoni, Simona; Macci, Cristina; Oliveri, Salvatore; Trovato, Laura; Dipineto, Ludovico; Rickerts, Volker; McCormick-Smith, Ilka; Akcaglar, Sevim; Tore, Okan; Mlinaric-Missoni, Emilija; Bertout, Sebastien; Mallié, Michele; Martins, Maria da Luz; Vencà, Ana C F; Vieira, Maria L; Sampaio, Ana C; Pereira, Cheila; Criseo, Giuseppe; Romeo, Orazio; Ranque, Stéphane; Al-Yasiri, Mohammed H Y; Kaya, Meltem; Cerikcioglu, Nilgun; Marchese, Anna; Vezzulli, Luigi; Ilkit, Macit; Desnos-Ollivier, Marie; Pasquale, Vincenzo; Korem, Maya; Polacheck, Itzhack; Scopa, Antonio; Meyer, Wieland; Ferreira-Paim, Kennio; Hagen, Ferry; Theelen, Bart; Boekhout, Teun; Lockhart, Shawn R; Tintelnot, Kathrin; Tortorano, Anna Maria; Dromer, Françoise; Varma, Ashok; Kwon-Chung, Kyung J; Inácio, Joäo; Alonso, Beatriz; Colom, Maria F

2016-06-01

In order to elucidate the distribution of Cryptococcus neoformans and C. gattii in the Mediterranean basin, an extensive environmental survey was carried out during 2012-2015. A total of 302 sites located in 12 countries were sampled, 6436 samples from 3765 trees were collected and 5% of trees were found to be colonized by cryptococcal yeasts. Cryptococcus neoformans was isolated from 177 trees and C. gattii from 13. Cryptococcus neoformans colonized 27% of Ceratonia, 10% of Olea, Platanus and Prunus trees and a lower percentage of other tree genera. The 13 C. gattii isolates were collected from five Eucalyptus, four Ceratonia, two Pinus and two Olea trees. Cryptococcus neoformans was distributed all around the Mediterranean basin, whereas C. gattii was isolated in Greece, Southern Italy and Spain, in agreement with previous findings from both clinical and environmental sources. Among C. neoformans isolates, VNI was the prevalent molecular type but VNII, VNIV and VNIII hybrid strains were also isolated. With the exception of a single VGIV isolate, all C. gattii isolates were VGI. The results confirmed the presence of both Cryptococcus species in the Mediterranean environment, and showed that both carob and olive trees represent an important niche for these yeasts. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Cryptococcus neoformans Is Internalized by Receptor-Mediated or ‘Triggered’ Phagocytosis, Dependent on Actin Recruitment

PubMed Central

Guerra, Caroline Rezende; Seabra, Sergio Henrique; de Souza, Wanderley; Rozental, Sonia

2014-01-01

Cryptococcosis by the encapsulated yeast Cryptococcus neoformans affects mostly immunocompromised individuals and is a frequent neurological complication in AIDS patients. Recent studies support the idea that intracellular survival of Cryptococcus yeast cells is important for the pathogenesis of cryptococcosis. However, the initial steps of Cryptococcus internalization by host cells remain poorly understood. Here, we investigate the mechanism of Cryptococcus neoformans phagocytosis by peritoneal macrophages using confocal and electron microscopy techniques, as well as flow cytometry quantification, evaluating the importance of fungal capsule production and of host cell cytoskeletal elements for fungal phagocytosis. Electron microscopy analyses revealed that capsular and acapsular strains of C. neoformans are internalized by macrophages via both ‘zipper’ (receptor-mediated) and ‘trigger’ (membrane ruffle-dependent) phagocytosis mechanisms. Actin filaments surrounded phagosomes of capsular and acapsular yeasts, and the actin depolymerizing drugs cytochalasin D and latrunculin B inhibited yeast internalization and actin recruitment to the phagosome area. In contrast, nocodazole and paclitaxel, inhibitors of microtubule dynamics decreased internalization but did not prevent actin recruitment to the site of phagocytosis. Our results show that different uptake mechanisms, dependent on both actin and tubulin dynamics occur during yeast internalization by macrophages, and that capsule production does not affect the mode of Cryptococcus uptake by host cells. PMID:24586631

Cryptococcus neoformans is internalized by receptor-mediated or 'triggered' phagocytosis, dependent on actin recruitment.

PubMed

Guerra, Caroline Rezende; Seabra, Sergio Henrique; de Souza, Wanderley; Rozental, Sonia

2014-01-01

Cryptococcosis by the encapsulated yeast Cryptococcus neoformans affects mostly immunocompromised individuals and is a frequent neurological complication in AIDS patients. Recent studies support the idea that intracellular survival of Cryptococcus yeast cells is important for the pathogenesis of cryptococcosis. However, the initial steps of Cryptococcus internalization by host cells remain poorly understood. Here, we investigate the mechanism of Cryptococcus neoformans phagocytosis by peritoneal macrophages using confocal and electron microscopy techniques, as well as flow cytometry quantification, evaluating the importance of fungal capsule production and of host cell cytoskeletal elements for fungal phagocytosis. Electron microscopy analyses revealed that capsular and acapsular strains of C. neoformans are internalized by macrophages via both 'zipper' (receptor-mediated) and 'trigger' (membrane ruffle-dependent) phagocytosis mechanisms. Actin filaments surrounded phagosomes of capsular and acapsular yeasts, and the actin depolymerizing drugs cytochalasin D and latrunculin B inhibited yeast internalization and actin recruitment to the phagosome area. In contrast, nocodazole and paclitaxel, inhibitors of microtubule dynamics decreased internalization but did not prevent actin recruitment to the site of phagocytosis. Our results show that different uptake mechanisms, dependent on both actin and tubulin dynamics occur during yeast internalization by macrophages, and that capsule production does not affect the mode of Cryptococcus uptake by host cells.

Predominance of Cryptococcus neoformans var. grubii multilocus sequence type 5 and emergence of isolates with non-wild-type minimum inhibitory concentrations to fluconazole: a multi-centre study in China.

PubMed

Fan, X; Xiao, M; Chen, S; Kong, F; Dou, H-T; Wang, H; Xiao, Y-L; Kang, M; Sun, Z-Y; Hu, Z-D; Wan, Z; Chen, S-L; Liao, K; Chu, Y-Z; Hu, T-S; Zou, G-L; Hou, X; Zhang, L; Zhao, Y-P; Xu, Y-C; Liu, Z-Y

2016-10-01

There are few data on the molecular epidemiology of cryptococcosis in China. Here we investigated the species distribution, molecular types and antifungal susceptibilities of 312 Cryptococcus neoformans species complex isolates from ten hospitals over 5 years. Isolates were identified by internal transcribed spacer (ITS) sequencing and by two matrix-assisted laser desorption-ionization time-of-flight mass spectrometry (MALDI-TOF MS) systems. Multilocus sequence typing (MLST) was used to verify species/variety and to designate molecular types. Susceptibility to six antifungal drugs was determined by the Sensititre YeastOne™ method. Cryptococcus neoformans was the predominant species (305/312 isolates (97.8%), all were ITS type 1, serotype A), of which 89.2% (272/305) were C. neoformans var. grubii MLST sequence type (ST) 5 and 6.2% (19/305) were ST31. Other C. neoformans var. grubii STs were rare but included six novel STs. Only two strains were C. neoformans var. neoformans (both serotype AD). Cryptococcus gattii was uncommon (n = 7, four ITS types) and comprised five MLST STs including one novel ST. For C. neoformans var. grubii, the proportion of isolates with non-wild-type MICs to fluconazole significantly rose in the fourth study year (from 0% (0/56 isolates) in the first year to 23.9% (17/71) in the fourth year), including five isolates with fluconazole MICs of ≥32 mg/L. The study has provided useful data on the species epidemiology and their genetic diversity and antifungal susceptibility. The proportional increase in isolates with non-wild-type MICs to fluconazole is noted. Copyright © 2016 European Society of Clinical Microbiology and Infectious Diseases. Published by Elsevier Ltd. All rights reserved.

Molecular epidemiology and in vitro antifungal susceptibility testing of 108 clinical Cryptococcus neoformans sensu lato and Cryptococcus gattii sensu lato isolates from Denmark.

PubMed

Hagen, Ferry; Hare Jensen, Rasmus; Meis, Jacques F; Arendrup, Maiken Cavling

2016-09-01

Cryptococcosis is mainly caused by members of the Cryptococcus gattii/Cryptococcus neoformans species complexes. Here, we report the molecular characterisation and in vitro antifungal susceptibility of Danish clinical cryptococcal isolates. Species, genotype, serotype and mating type were determined by amplified fragment length polymorphism (AFLP) fingerprinting and qPCR. EUCAST E.Def 7.2 MICs were determined for amphotericin B, flucytosine, fluconazole, voriconazole and isavuconazole. Most isolates were C. neoformans (serotype A; n = 66) and belonged to genotype AFLP1/VNI (n = 61) or AFLP1B/VNII (n = 5) followed by Cryptococcus deneoformans (serotype D; genotype AFLP2, n = 20), C. neoformans × C. deneoformans hybrids (serotype AD; genotype AFLP3, n = 13) and Cryptococcus curvatus (n = 2). Six isolates were C. gattii sensu lato, and one isolate was a C. deneoformans × C. gattii hybrid (genotype AFLP8). All isolates were amphotericin B susceptible. Flucytosine susceptibility was uniform MIC50 of 4-8 mg l(-1) except for C. curvatus (MICs >32 mg l(-1) ). Cryptococcus gattii sensu lato isolates were somewhat less susceptible to the azoles. MICs of fluconazole (>32 mg l(-1) ), voriconazole (≥0.5 mg l(-1) ) and isavuconazole (0.06 and 0.25 mg l(-1) respectively) were elevated compared to the wild-type population for 1/19 C. deneoformans and 1/2 C. curvatus isolates. Flucytosine MIC was elevated for 1/61 C. neoformans (>32 mg l(-1) ). Antifungal susceptibility revealed species-specific differential susceptibility, but suggested acquired resistance was an infrequent phenomenon. © 2016 Blackwell Verlag GmbH.

The Intracellular Life of Cryptococcus neoformans

PubMed Central

Coelho, Carolina; Bocca, Anamelia L.; Casadevall, Arturo

2016-01-01

Cryptococcus neoformans is a fungal pathogen with worldwide distribution. Serological studies of human populations show a high prevalence of human infection, which rarely progresses to disease in immunocompetent hosts. However, decreased host immunity places individuals at high risk for cryptococcal disease. The disease can result from acute infection or reactivation of latent infection, in which yeasts within granulomas and host macrophages emerge to cause disease. In this review, we summarize what is known about the cellular recognition, ingestion, and killing of C. neoformans and discuss the unique and remarkable features of its intracellular life, including the proposed mechanisms for fungal persistence and killing in phagocytic cells. PMID:24050625

Enhanced resistance of the Pamirs high-mountain strain of Cryptococcus albidus to UV radiation of an ecological range

DOE Office of Scientific and Technical Information (OSTI.GOV)

Strakhovskaya, M.G.; Lavrukhina, O.G.; Fraikin, G.Y.

The results of a comparative analysis of the resistance of Pamirs high-mountain and lowland strains of the yeast Cryptococcus albidus to UV radiation of an ecological range are presented. A high-mountain strain, adapted to elevated UV radiation in its habitat, was found to be more resistant to UV light of a total ecorange (290-400 nm), including medium-wave (290-320 nm) and long-wave (320-400 nm) UV ranges. The enhanced UV light resistance of the high-mountain strain can be explained by efficient functioning of the excision DNA repair system. 7 refs., 3 tabs.

Pneumocystis Jiroveci Pneumonia

DTIC Science & Technology

2008-10-01

patients with AIDS include CMV pneumonia, lymphocytic interstitial pneumonia, MAI infection, cryptococcal infection, Legionella , Mycoplasma...negative for Legionella , Streptococcus pneumoniae, and Cryptococcus neoformans. Pneumocystis direct fluorescent antibody (DFA) of the fluid was also

Ecoepidemiology of Cryptococcus gattii in Developing Countries

PubMed Central

Hagen, Ferry; Pinheiro, Rosangela L.; Muro, Marisol D.; Meis, Jacques F.; Queiroz-Telles, Flávio

2017-01-01

Cryptococcosis is a systemic infection caused by species of the encapsulated yeast Cryptococcus. The disease may occur in immunocompromised and immunocompetent hosts and is acquired by the inhalation of infectious propagules present in the environment. Cryptococcus is distributed in a plethora of ecological niches, such as soil, pigeon droppings, and tree hollows, and each year new reservoirs are discovered, which helps researchers to better understand the epidemiology of the disease. In this review, we describe the ecoepidemiology of the C. gattii species complex focusing on clinical cases and ecological reservoirs in developing countries from different continents. We also discuss some important aspects related to the antifungal susceptibility of different species within the C. gattii species complex and bring new insights on the revised Cryptococcus taxonomy. PMID:29371578

Structural analysis of glucosylceramides (GlcCer) from species of the Pseudallescheria/Scedosporium complex.

PubMed

Calixto, Renata O R; Rollin-Pinheiro, Rodrigo; da Silva, Mariana I D; Liporagi-Lopes, Livia C; Vieira, Jardel M; Sassaki, Guilherme L; Barreto-Bergter, Eliana

2016-02-01

Glucosylceramides (GlcCer) are the main neutral glycosphingolipids expressed in fungal cells. In this work, glucosylceramides (GlcCer) were extracted from three strains of Scedosporium (Pseudallescheria) boydii, one strain of Pseudallescheria ellipsoidea and one strain of Pseudallescheria angusta and purified by several chromatographic steps. Using high-performance thin layer chromatography (HPTLC), we found a similarity between GlcCer obtained from all of the analysed strains. A detailed structural analysis of the P. ellipsoidea GlcCer was performed via electrospray ionization mass spectrometry (ESI-MS) and confirmed in 1- and 2-D heteronuclear NMR experiments ((1)H-(13) C HSQC). GlcCer species produced by mycelial forms of these strains displayed the same structure previously demonstrated by our group for P. boydii, Cryptococcus neoformans, Pseudallescheria minustipora, Fusarium solani, and Colletotrichum gloesporioides. A monoclonal antibody (mAb) against GlcCer was used for immunofluorescence experiments. Our results revealed that GlcCer is present on the surface of these fungi, and no difference was observed in the GlcCer structure of the present set of strains in terms of geographic or clinical origin, suggesting a conserved GlcCer structure similar to those previously described for Scedosporium apiospermum, Scedosporium aurantiacum, and P. minutispora. The surface distribution of GlcCer in these fungi is suggestive of the involvement of this molecule in fungal growth. Copyright © 2015 The British Mycological Society. Published by Elsevier Ltd. All rights reserved.

Occurrence of dermatophytes in fresh bat guano.

PubMed

Kajihiro, E S

1965-09-01

Evidence is presented in support of the hypothesis that fresh bat guano serves as a means of pathogenic fungi dissemination in caves. A total of 371 guano samples were collected from caves in southeastern New Mexico. Each sample was agitated in sterile saline and sand. The supernatant fluid was treated with an antibiotic and streaked on differential media. Cultures were incubated at 25 and 37 C and examined at intervals over a 4-week period. For animal inoculation, highly concentrated inoculum was injected intraperitoneally into white Swiss mice. Animals were sacrificed 4 weeks later, and portions of their lung, liver, and spleen were cultured on selective media, incubated at 25 C, and examined at intervals over a 4-week period. Microsporum gypseum was isolated at all 10 collecting stations with an incidence of 22.4%, Trichophyton mentagrophytes at 7 stations with an incidence of 5%, T. rubrum at 3 stations with an incidence of 3%, and T. terrestre at 1 station with an incidence of 0.5%. From a total of 60 pools of liver-spleen-lung suspensions, 6 pools yielded positive cultures of Histoplasma capsulatum and 1 pool yielded T. mentagrophytes. No significant difference was found among the different selective media with respect to recovery of dermatophytes. Among the human pathogenic fungi isolated were Candida sp., Cladosporium sp., Coccidioides immitis, Cryptococcus neoformans, H. capsulatum, M. gypseum, T. mentagrophytes, T. rubrum, T. terrestre, and Sporotrichum sp.

Creation, characterization and utilization of Cryptococcus neoformans mutants sensitive to micafungin.

PubMed

Toh-E, Akio; Ohkusu, Misako; Shimizu, Kiminori; Yamaguchi, Masashi; Ishiwada, Naruhiko; Watanabe, Akira; Kamei, Katsuhiko

2017-12-01

We constructed deletion mutants of Cryptococcus neoformans var neoformans (serotype D) genes encoding late ergosterol biosynthetic pathway enzymes and found that the mutations enhanced susceptibility to various drugs including micafungin, one of the echinocandins, to which wild-type Cryptococcus strains show no susceptibility. Furthermore, through isolation of a mutant resistant to micafungin from a micafungin-sensitive erg mutant and genetic analysis of it, we found that the responsible mutation occurred in the hotspot 2 of FKS1 encoding β-1, 3-glucan synthase, indicating that micafungin inhibited the growth of the erg mutant via inhibiting Fks1 activity. Addition of ergosterol to the culture of the erg mutants recovered the resistance to micafungin, suggesting that the presence of ergosterol in membrane inhibits the accession of micafungin to its target. We found that a loss of one of genes encoding subunits of v-ATPase, VPH1, made Cryptococcus cells sensitive to micafungin. Our observation that the erg2 vph1 double mutant was more sensitive to micafungin than either single mutant suggests that these two genes act differently in becoming resistant to micafungin. The erg mutants allowed us to study the physiological significance of β-1, 3-glucan synthesis in C. neoformans; the inhibition of β-1, 3-glucan synthesis induced cell death and changes in cellular morphology. By observing the erg mutant cells recovering from the growth inhibition imposed by micafungin, we recognized β-1, 3-glucan synthesis would suppress filamentous growth in C. neoformans.

Repurposing of Aspirin and Ibuprofen as Candidate Anti-Cryptococcus Drugs.

PubMed

Ogundeji, Adepemi O; Pohl, Carolina H; Sebolai, Olihile M

2016-08-01

The usage of fluconazole and amphotericin B in clinical settings is often limited by, among other things, drug resistance development and undesired side effects. Thus, there is a constant need to find new drugs to better manage fungal infections. Toward this end, the study described in this paper considered the repurposing of aspirin (acetylsalicylic acid) and ibuprofen as alternative drugs to control the growth of cryptococcal cells. In vitro susceptibility tests, including a checkerboard assay, were performed to assess the response of Cryptococcus neoformans and Cryptococcus gattii to the above-mentioned anti-inflammatory drugs. Next, the capacity of these two drugs to induce stress as well as their mode of action in the killing of cryptococcal cells was determined. The studied fungal strains revealed a response to both aspirin and ibuprofen that was dose dependent, with ibuprofen exerting greater antimicrobial action. More importantly, the MICs of these drugs did not negatively (i) affect growth or (ii) impair the functioning of macrophages; rather, they enhanced the ability of these immune cells to phagocytose cryptococcal cells. Ibuprofen was also shown to act in synergy with fluconazole and amphotericin B. The treatment of cryptococcal cells with aspirin or ibuprofen led to stress induction via activation of the high-osmolarity glycerol (HOG) pathway, and cell death was eventually achieved through reactive oxygen species (ROS)-mediated membrane damage. The presented data highlight the potential clinical application of aspirin and ibuprofen as candidate anti-Cryptococcus drugs. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

Clinical features and epidemiology of cryptococcosis in cats and dogs in California: 93 cases (1988-2010).

PubMed

Trivedi, Sameer R; Sykes, Jane E; Cannon, Matthew S; Wisner, Erik R; Meyer, Wieland; Sturges, Beverly K; Dickinson, Peter J; Johnson, Lynelle R

2011-08-01

To compare clinical features of cryptococcosis among cats and dogs in California, determine whether the distribution of involved tissues differs from distribution reported previously in a study in southeastern Australia, and identify Cryptococcus spp isolated from the study population. Retrospective case series. 62 cats and 31 dogs with cryptococcosis. Medical records of cats and dogs with cryptococcosis were reviewed. Information collected included geographic location, species, signalment, and tissues or organs involved. Cryptococcosis was confirmed via serology, cytology, histology, or microbial culture, and molecular typing was performed. Odds ratios and 95% confidence intervals were calculated to determine significant associations among variables. Other comparisons were evaluated via χ(2) or unpaired t tests. American Cocker Spaniels were overrepresented, compared with other dog breeds. Serum cryptococcal antigen test results were positive in 51 of 53 cats and 15 of 18 dogs tested. Cryptococcus gattii was more commonly detected in cats (7/9 for which species identification was performed), and Cryptococcus neoformans was more commonly detected in dogs (6/8). Six of 7 C gattii isolates from cats were molecular type VGIII. Distribution of involved tissues was different between cats and dogs in California and between populations of the present study and those of the previously reported Australian study. Strains of Cryptococcus spp appeared to have host specificity in dogs and cats. Differences in lesion distribution between geographic locations may reflect strain differences or referral bias. Antigen assays alone may not be sufficient for diagnosis of cryptococcosis in cats and dogs.

Ferrets as sentinels of the presence of pathogenic Cryptococcus species in the Mediterranean environment.

PubMed

Morera, Neus; Hagen, Ferry; Juan-Sallés, Carles; Artigas, Carlos; Patricio, Rui; Serra, Juan Ignacio; Colom, Ma Francisca

2014-08-01

Cryptococcus gattii is a pathogenic environmental yeast that is considered to be emerging in different areas of the world including the Mediterranean Basin. Exposure to infection might be more likely in animals than in human beings, given their closer relationship with the natural habitat of the yeast, vegetation and soil. Thus, animals, and especially pets, can act as indicators of the presence of this yeast in a determined area. Domestic ferrets (Mustela putorius furo) have become common pets in the past 10-20 years. Their natural behavior of sniffing around and going inside narrow spaces makes them prone to contact with decaying organic matter and soil, the substrate for Cryptococcus species. This study describes two cases of cryptococcosis in ferrets in the Iberian Peninsula and Balearic Islands and documents a relationship of ferret cryptococcosis with environmental isolates in the same locations. Here, we emphasize the importance of how an adequate identification and environmental search of the yeast leads to a better understanding of the epidemiology of cryptococcosis and suggests ferrets may act as sentinels for this fungal disease.

Capsules from pathogenic and non-pathogenic Cryptococcus spp. manifest significant differences in structure and ability to protect against phagocytic cells.

PubMed

Araujo, Glauber de S; Fonseca, Fernanda L; Pontes, Bruno; Torres, Andre; Cordero, Radames J B; Zancopé-Oliveira, Rosely M; Casadevall, Arturo; Viana, Nathan B; Nimrichter, Leonardo; Rodrigues, Marcio L; Garcia, Eloi S; Souza, Wanderley de; Frases, Susana

2012-01-01

Capsule production is common among bacterial species, but relatively rare in eukaryotic microorganisms. Members of the fungal Cryptococcus genus are known to produce capsules, which are major determinants of virulence in the highly pathogenic species Cryptococcus neoformans and Cryptococcus gattii. Although the lack of virulence of many species of the Cryptococcus genus can be explained solely by the lack of mammalian thermotolerance, it is uncertain whether the capsules from these organisms are comparable to those of the pathogenic cryptococci. In this study, we compared the characteristic of the capsule from the non-pathogenic environmental yeast Cryptococcus liquefaciens with that of C. neoformans. Microscopic observations revealed that C. liquefaciens has a capsule visible in India ink preparations that was also efficiently labeled by three antibodies generated to specific C. neoformans capsular antigens. Capsular polysaccharides of C. liquefaciens were incorporated onto the cell surface of acapsular C. neoformans mutant cells. Polysaccharide composition determinations in combination with confocal microscopy revealed that C. liquefaciens capsule consisted of mannose, xylose, glucose, glucuronic acid, galactose and N-acetylglucosamine. Physical chemical analysis of the C. liquefaciens polysaccharides in comparison with C. neoformans samples revealed significant differences in viscosity, elastic properties and macromolecular structure parameters of polysaccharide solutions such as rigidity, effective diameter, zeta potential and molecular mass, which nevertheless appeared to be characteristics of linear polysaccharides that also comprise capsular polysaccharide of C. neoformans. The environmental yeast, however, showed enhanced susceptibility to the antimicrobial activity of the environmental phagocytes, suggesting that the C. liquefaciens capsular components are insufficient in protecting yeast cells against killing by amoeba. These results suggest that capsular structures in pathogenic Cryptococcus species and environmental species share similar features, but also manifest significant difference that could influence their potential to virulence.

Antifungal drug susceptibility and phylogenetic diversity among Cryptococcus isolates from dogs and cats in North America.

PubMed

Singer, Lisa M; Meyer, Wieland; Firacative, Carolina; Thompson, George R; Samitz, Eileen; Sykes, Jane E

2014-06-01

Molecular types of the Cryptococcus neoformans/Cryptococcus gattii species complex that infect dogs and cats differ regionally and with host species. Antifungal drug susceptibility can vary with molecular type, but the susceptibility of Cryptococcus isolates from dogs and cats is largely unknown. Cryptococcus isolates from 15 dogs and 27 cats were typed using URA5 restriction fragment length polymorphism analysis (RFLP), PCR fingerprinting, and multilocus sequence typing (MLST). Susceptibility was determined using a microdilution assay (Sensititre YeastOne; Trek Diagnostic Systems). MICs were compared among groups. The 42 isolates studied comprised molecular types VGI (7%), VGIIa (7%), VGIIb (5%), VGIIc (5%), VGIII (38%), VGIV (2%), VNI (33%), and VNII (2%), as determined by URA5 RFLP. The VGIV isolate was more closely related to VGIII according to MLST. All VGIII isolates were from cats. All sequence types identified from veterinary isolates clustered with isolates from humans. VGIII isolates showed considerable genetic diversity compared with other Cryptococcus molecular types and could be divided into two major subgroups. Compared with C. neoformans MICs, C. gattii MICs were lower for flucytosine, and VGIII MICs were lower for flucytosine and itraconazole. For all drugs except itraconazole, C. gattii isolates exhibited a wider range of MICs than C. neoformans. MICs varied with Cryptococcus species and molecular type in dogs and cats, and MICs of VGIII isolates were most variable and may reflect phylogenetic diversity in this group. Because sequence types of dogs and cats reflect those infecting humans, these observations may also have implications for treatment of human cryptococcosis. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

[Canine lymphadenitis caused by Cryptococcus neoformans. First case in Chile].

PubMed

Thomson, Pamela; Miranda, Gabriel; Silva, Víctor

2006-12-01

We report the first case of canine lymphoadenomegalia caused by Cryptococcus neoformans in Chile. Physical examination of a Rottweiler dog patient showed a generalized lymphoadenomegalia that affected the submandibular, superficial cervical and popliteus lymphatic nodules. Cryptococcus neoformans was isolated and identified from biopsies of the right submandibular nodule. After antifungal susceptibility, oral ketoconazole treatment was established for a period of six months showing clinical improvement. Two years post-treatment the patient showed no signs of the infection.

Determining Antifungal Target Sites in the Sterol Pathway of the Yeasts Candida and Saccharomyces

DTIC Science & Technology

1999-10-01

Cryptococcus (19, 33), and the cloning of the LISI gene (35), mutants of which were Aspergillus (9), have been the subjects of recent reports on selected...cells to bleomycin. 1997. Fluconazole tolerance in clinical isolates of Cryptococcus neoformans. Anticancer Res. 14:1711-1721. Antimicrob. Agents...1482-1487. cytoehrome P-450 monooxygenase system isolated from Cryptococcus neo- 38. White, T. 1997. The presence of an R467K amino acid substitution

The expanding host tree species spectrum of Cryptococcus gattii and Cryptococcus neoformans and their isolations from surrounding soil in India.

PubMed

Randhawa, H S; Kowshik, T; Chowdhary, Anuradha; Preeti Sinha, K; Khan, Z U; Sun, Sheng; Xu, Jianping

2008-12-01

This study reports the widespread prevalence of Cryptococcus neoformans and Cryptococcus gattii in decayed wood inside trunk hollows of 14 species representing 12 families of trees and from soil near the base of various host trees from Delhi and several places in the Indian states of Uttar Pradesh, Haryana, Tamil Nadu and Chandigarh Union Territory. Of the 311 trees from which samples were obtained, 64 (20.5%) were found to contain strains of the C. neoformans species complex. The number of trees positive for C. neoformans var grubii (serotypeA) was 51 (16.3%), for C. gattii (serotype B) 24 (7.7%) and for both C. neoformans and C. gattii 11 (3.5%). The overall prevalence of C. neoformans species complex in decayed wood samples was 19.9% (111/556). There was no obvious correlation between the prevalence of these two yeast species and the species of host trees. The data on prevalence of C. gattii (24%) and C. neoformans (26%) in soil around the base of some host trees indicated that soil is another important ecologic niche for these two Cryptococcus species in India. Among our sampled tree species, eight and six were recorded for the first time as hosts for C. neoformans var grubii and C. gattii, respectively. A longitudinal surveillance of 8 host tree species over 0.7 to 2.5 years indicated long term colonization of Polyalthia longifolia, Mimusops elengi and Manilkara hexandra trees by C. gattii and/or C. neoformans. The mating type was determined for 153 of the isolates, including 98 strains of serotype A and 55 of serotype B and all proved to be mating type alpha (MAT alpha). Our observations document the rapidly expanding spectrum of host tree species for C. gattii and C. neoformans and indicate that decayed woods of many tree species are potentially suitable ecological niches for both pathogens.

Isolation of Cryptococcus laurentii from Canada Goose guano in rural upstate New York.

PubMed

Filion, Tera; Kidd, Sarah; Aguirre, Karen

2006-11-01

Cryptococcus neoformans and Cryptococcus gattii are etiologic agents of cryptococcal pneumonia and meningitis, potentially lethal syndromes associated with AIDS. A related species, Cryptococcus laurentii, has recently been implicated in several cases of human disease. Guano from Canada Goose (Branta canadensis), an organism that lives closely beside man and inhabits recreational space in rural and suburban areas, might be a significant environmental reservoir of Cryptococcus organisms in non-urban areas. Cryptococcal organisms were isolated from Canada Goose guano from a site in rural northern New York, with identification based upon colony and microscopic morphology, ability to metabolize L: -Dopa to melanin, and positive reaction with a commercial anti-cryptococcal capsular polysaccharide latex bead agglutination test. DNA sequences from five positive isolates were identical to each other, and identical to the ITS1-5.8S-ITS2 sequences of C. laurentii strain CBS7140 (Accession AY315665) across a 511 bp sequence. All five isolates of C. laurentii possess three of the known virulence factors common to cryptococcal organisms that cause human disease: capsule, ability to grow at 37 degrees C, and laccase activity.

Allelic exchange of pheromones and their receptors reprograms sexual identity in Cryptococcus neoformans.

PubMed

Stanton, Brynne C; Giles, Steven S; Staudt, Mark W; Kruzel, Emilia K; Hull, Christina M

2010-02-26

Cell type specification is a fundamental process that all cells must carry out to ensure appropriate behaviors in response to environmental stimuli. In fungi, cell identity is critical for defining "sexes" known as mating types and is controlled by components of mating type (MAT) loci. MAT-encoded genes function to define sexes via two distinct paradigms: 1) by controlling transcription of components common to both sexes, or 2) by expressing specially encoded factors (pheromones and their receptors) that differ between mating types. The human fungal pathogen Cryptococcus neoformans has two mating types (a and alpha) that are specified by an extremely unusual MAT locus. The complex architecture of this locus makes it impossible to predict which paradigm governs mating type. To identify the mechanism by which the C. neoformans sexes are determined, we created strains in which the pheromone and pheromone receptor from one mating type (a) replaced the pheromone and pheromone receptor of the other (alpha). We discovered that these "alpha(a)" cells effectively adopt a new mating type (that of a cells); they sense and respond to alpha factor, they elicit a mating response from alpha cells, and they fuse with alpha cells. In addition, alpha(a) cells lose the alpha cell type-specific response to pheromone and do not form germ tubes, instead remaining spherical like a cells. Finally, we discovered that exogenous expression of the diploid/dikaryon-specific transcription factor Sxi2a could then promote complete sexual development in crosses between alpha and alpha(a) strains. These data reveal that cell identity in C. neoformans is controlled fully by three kinds of MAT-encoded proteins: pheromones, pheromone receptors, and homeodomain proteins. Our findings establish the mechanisms for maintenance of distinct cell types and subsequent developmental behaviors in this unusual human fungal pathogen.

Characterization of the Complete Uric Acid Degradation Pathway in the Fungal Pathogen Cryptococcus neoformans

PubMed Central

Lee, I. Russel; Yang, Liting; Sebetso, Gaseene; Allen, Rebecca; Doan, Thi H. N.; Blundell, Ross; Lui, Edmund Y. L.; Morrow, Carl A.; Fraser, James A.

2013-01-01

Degradation of purines to uric acid is generally conserved among organisms, however, the end product of uric acid degradation varies from species to species depending on the presence of active catabolic enzymes. In humans, most higher primates and birds, the urate oxidase gene is non-functional and hence uric acid is not further broken down. Uric acid in human blood plasma serves as an antioxidant and an immune enhancer; conversely, excessive amounts cause the common affliction gout. In contrast, uric acid is completely degraded to ammonia in most fungi. Currently, relatively little is known about uric acid catabolism in the fungal pathogen Cryptococcus neoformans even though this yeast is commonly isolated from uric acid-rich pigeon guano. In addition, uric acid utilization enhances the production of the cryptococcal virulence factors capsule and urease, and may potentially modulate the host immune response during infection. Based on these important observations, we employed both Agrobacterium-mediated insertional mutagenesis and bioinformatics to predict all the uric acid catabolic enzyme-encoding genes in the H99 genome. The candidate C. neoformans uric acid catabolic genes identified were named: URO1 (urate oxidase), URO2 (HIU hydrolase), URO3 (OHCU decarboxylase), DAL1 (allantoinase), DAL2,3,3 (allantoicase-ureidoglycolate hydrolase fusion protein), and URE1 (urease). All six ORFs were then deleted via homologous recombination; assaying of the deletion mutants' ability to assimilate uric acid and its pathway intermediates as the sole nitrogen source validated their enzymatic functions. While Uro1, Uro2, Uro3, Dal1 and Dal2,3,3 were demonstrated to be dispensable for virulence, the significance of using a modified animal model system of cryptococcosis for improved mimicking of human pathogenicity is discussed. PMID:23667704

Characterization of the complete uric acid degradation pathway in the fungal pathogen Cryptococcus neoformans.

PubMed

Lee, I Russel; Yang, Liting; Sebetso, Gaseene; Allen, Rebecca; Doan, Thi H N; Blundell, Ross; Lui, Edmund Y L; Morrow, Carl A; Fraser, James A

2013-01-01

Degradation of purines to uric acid is generally conserved among organisms, however, the end product of uric acid degradation varies from species to species depending on the presence of active catabolic enzymes. In humans, most higher primates and birds, the urate oxidase gene is non-functional and hence uric acid is not further broken down. Uric acid in human blood plasma serves as an antioxidant and an immune enhancer; conversely, excessive amounts cause the common affliction gout. In contrast, uric acid is completely degraded to ammonia in most fungi. Currently, relatively little is known about uric acid catabolism in the fungal pathogen Cryptococcus neoformans even though this yeast is commonly isolated from uric acid-rich pigeon guano. In addition, uric acid utilization enhances the production of the cryptococcal virulence factors capsule and urease, and may potentially modulate the host immune response during infection. Based on these important observations, we employed both Agrobacterium-mediated insertional mutagenesis and bioinformatics to predict all the uric acid catabolic enzyme-encoding genes in the H99 genome. The candidate C. neoformans uric acid catabolic genes identified were named: URO1 (urate oxidase), URO2 (HIU hydrolase), URO3 (OHCU decarboxylase), DAL1 (allantoinase), DAL2,3,3 (allantoicase-ureidoglycolate hydrolase fusion protein), and URE1 (urease). All six ORFs were then deleted via homologous recombination; assaying of the deletion mutants' ability to assimilate uric acid and its pathway intermediates as the sole nitrogen source validated their enzymatic functions. While Uro1, Uro2, Uro3, Dal1 and Dal2,3,3 were demonstrated to be dispensable for virulence, the significance of using a modified animal model system of cryptococcosis for improved mimicking of human pathogenicity is discussed.

Searching for eukaryotic life preserved in Antarctic permafrost

NASA Astrophysics Data System (ADS)

Onofri, Silvano; Zucconi, Laura; Selbmann, Laura; Ripa, Caterina; Frisvad, Jens Christian; Guglielmin, Mauro; Turchetti, Benedetta; Buzzini, Pietro

Permafrost is defined as a soil remaining at 0 C or below throughout two or more consecutive years. Mainly present in polar areas, it occurs in all ice-free areas of Continental Antarc-tica. With the evidences of the possible presence of water ice below the surface of Mars and Moon, permafrost is now considered a possible reservoir of prokaryotic and eukaryotic spores outside the Earth. Cultivable fungi and yeasts have been isolated from Antarctic permafrost collected at different depths (233, 316 and 335 cm) in the McMurdo Dry Valleys, the largest ice-free area in Antarctica, and identified with cultural, physiological and molecular methods. Filamentous fungi belonged to the genera Penicillium, Eurotium, Cladosporium, Alternaria, Engyodonthium, Cordiceps, Rhizopus, Aureobasidium, whereas yeasts belonged to the genera Cryptococcus and Sporidiobolus. Penicillia were the most represented, and the most frequently recorded species were Penicillium palitans and P. chrysogenum. Most of the species found have been already recorded in Antarctic ecosystems as well as in other cold habitats (Onofri et al., 2007); for Eurotium amstelodami and Cryptococcus stepposus these are the first isolations in Antarctica. All the filamentous fungal isolates can be defined as mesophilic having optimal growth temperatures at 20-25 C and poor growth at 0 C after prolonged incubation. All the yeast isolates grew within a wide range of temperature (from 4 to 25 C). The molecular anal-yses based on the ITS rDNA sequences, for filamentous fungi, and on D1/D2 domain of LSU rRNA gene and ITS sequences for yeasts, revealed that these genotypes do not deviate from the global gene pool of microorganisms commonly spreading worldwide at present. Annual mean permafrost temperature (MAPT) in the sampling area was -18.8 C in 2008, with daily fluctuations lower than 1 C/day at 1 m of depth, but less 0.5 C/year at the depth of 17 m (Guglielmin pers. com.), and maximum thaw depth not exceeding 1 m. Therefore it could be expected that fungal propagules have remained trapped in permafrost layers for an estimated age of 10-12 (Kelly et al., 2002), up to 15-20 Kyears, rather than carried by natural contami-nation throughout permafrost layers as consequence of ice recharging (Gilichinsky et al., 2007), showing that viable fungal propagules can be preserved in permafrost for a quite long time. Gilichinsky D.A., Wilson G.S., Friedmann E.I., McKay C.P., Sletten R.S., Rivkina E.M., Vishnivetskaya T.A., Erokhina L.G., Ivanushkina N.E., Kochkina G.A., Shcherbakova V.A., Soina V.S., Spirina E.V., Vorobyova E.A., Fyodorov-Davydov D.G., Hallet B., Ozerskaya S.M., Sorokovikov V.A., Laurinavichyus K.S., Shatilovich A.V., Chanton J.P., Ostroumov V.E., Tiedje J.M., 2007. Microbial populations in Antarctic permafrost: biodiversity, state, age, and implication for astrobiology. Astrobiology 7(2): 275-311. Kelly A.M., Denton G.H., Hall B.L., 2002. Late Cenozoic paleoenvironment in southern Victoria Land, Antarctica, based on a polar glaciolacustrine deposit in western Vicoria Valley. Geological Society of America Bulletin 114(5): 605-618. Onofri S., Zucconi L., Tosi S., 2007. Continental Antarctic Fungi. IHW Verlag, Eching bei Munchen, 247 pp.

Cavitary Lung Disease in an HIV-Positive Patient

DTIC Science & Technology

2009-04-01

Cryptococcus neoformans, and cytomegalovirus. She was treated with anidulafungin for aspergillosis. Discussion Pulmonary cavitation begins with...Histoplasma, Coccidioides, Blastomyces) and opportunistic pathogens (Aspergillus, Cryptococcus , Zygomycetes, Pneumocystis) Parasites: Paragonimus

Antimicrobial assay and genetic screening of selected freshwater Cyanobacteria and identification of a biomolecule dihydro-2H-pyran-2-one derivative.

PubMed

Srivastava, A; Singh, V K; Patnaik, S; Tripathi, J; Singh, P; Nath, G; Asthana, R K

2017-04-01

Explorations of freshwater Cyanobacteria as antimicrobial (bacteria, fungi and methicillin-resistant Staphylococcus aureus (MRSA) strains) drug resource using bioassay, NRPS (non-ribosomal polypeptide synthetase) and PKS (polyketide synthase) genes, as well as in silico approach. We have bioassayed the extracts of Phormidium CCC727, Geitlerinema CCC728, Arthrospira CCC729, Leptolyngbya CCC732, Phormidium CCC730, Phormidium CCC731 against six pathogenic bacteria comprising Gram (+ve): S. aureus including seven clinical MRSA and Enterococcus faecalis, Gram (-ve): Escherichia coli, Salmonella Typhimurium, Klebsiella pneumoniae and Shigella boydii along with non-pathogenic Enterobacter aerogenes as well as fungal strains (Cryptococcus neoformans and Candida albicans, C. krusei, C. tropicalis and Aspergillus niger) exhibiting antimicrobial potential. The NRPS and PKS genes of the target strains were also amplified and sequenced. The putative protein structures were predicted using bioinformatics approach. PKS gene expression indicated β keto-acyl synthase as one of the important active domains in the biomolecules related to antitumour and antifungal group. The simultaneous identification of the biomolecule (dihydro-2H-pyran-2-one derivative) was also inferred spectroscopically. Freshwater Cyanobacteria are prolific producers of secondary metabolite(s) that may act as the antimicrobial drug resource in addition to their much explored marine counterpart. © 2016 The Society for Applied Microbiology.

The Celecoxib Derivative AR-12 Has Broad-Spectrum Antifungal Activity In Vitro and Improves the Activity of Fluconazole in a Murine Model of Cryptococcosis

PubMed Central

Koselny, Kristy; Green, Julianne; DiDone, Louis; Halterman, Justin P.; Fothergill, Annette W.; Wiederhold, Nathan P.; Patterson, Thomas F.; Cushion, Melanie T.; Rappelye, Chad; Wellington, Melanie

2016-01-01

Only one new class of antifungal drugs has been introduced into clinical practice in the last 30 years, and thus the identification of small molecules with novel mechanisms of action is an important goal of current anti-infective research. Here, we describe the characterization of the spectrum of in vitro activity and in vivo activity of AR-12, a celecoxib derivative which has been tested in a phase I clinical trial as an anticancer agent. AR-12 inhibits fungal acetyl coenzyme A (acetyl-CoA) synthetase in vitro and is fungicidal at concentrations similar to those achieved in human plasma. AR-12 has a broad spectrum of activity, including activity against yeasts (e.g., Candida albicans, non-albicans Candida spp., Cryptococcus neoformans), molds (e.g., Fusarium, Mucor), and dimorphic fungi (Blastomyces, Histoplasma, and Coccidioides) with MICs of 2 to 4 μg/ml. AR-12 is also active against azole- and echinocandin-resistant Candida isolates, and subinhibitory AR-12 concentrations increase the susceptibility of fluconazole- and echinocandin-resistant Candida isolates. Finally, AR-12 also increases the activity of fluconazole in a murine model of cryptococcosis. Taken together, these data indicate that AR-12 represents a promising class of small molecules with broad-spectrum antifungal activity. PMID:27645246

Cryptococcus laurentii diarrhea post hematopoietic stem cell transplant.

PubMed

Bhat, Vivek; Vira, Hemant; Khattry, Navin; Toshniwal, Manoj

2017-04-01

We report the recent isolation of Cryptococcus laurentii from the feces of a patient with Hodgkin's lymphoma who underwent autologous hematopoietic stem cell transplant (HSCT). The organism was identified using microscopic morphology, cultural characteristics, and biochemical tests including sugar assimilation. Minimum inhibitory concentration of various antifungals was determined by microbroth dilution method. The recovery of pure culture of C. laurentii from stool culture, and the patient's response to treatment with voriconazole support its potential etiological role. To the best of our knowledge, we report the first case of diarrhea caused by C. laurentii in an HSCT recipient. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

[Presumptive identification of Cryptococcus gattii isolated from Terminalia catappa in Montería city, Córdoba, Colombia].

PubMed

Contreras Martínez, Orfa Inés; Aycardi Morinelli, María Paulina; Alarcón Furnieles, Jany Luz; Jaraba Ramos, Aparicio Manuel

2011-01-01

the members of the Cryptococcus neoformans species complex are responsible for cryptococcosis in animals and humans. Human infection is thought to be acquired by inhalation of airborne propagules from an environmental source; therefore it is greatly important to study their habitat. to determine the ecological relationship of Cryptococcus gattii with Terminalia catappa trees present in urban areas of Montería city in Colombia. a total of 163 Terminalia catappa trees were selected; some samples were taken from the bark, the leaves, the flowers, the fruits of these trees and from the surrounding soil. The yeast was isolated using the Guizotia abyssinica seed agar medium; it was identified thanks to biochemical and morphologic tests whereas the right variety was determined by L-canavanine-glycine-bromothymol blue (CGB), D-proline and D-tryptophan tests. there was obtained 9.050 CFU/g isolate of Cryptococcus spp., 5.795 CFU/g of which were presumptively identified as Cryptococcus gattii. The highest percentage of isolates was found in flowers, followed by bark and fruits, presenting small cellular and capsular sizes. These isolates were more frequent in the south of the city, followed by the center zone and the lowest percentage in the northern zone. these findings confirmed the close relationship of Cryptococcus gattii and Terminalia catappa, being this the first study conducted in Monteria city. These results give us meaningful information for understanding and analyzing the epidemiology of cryptococcosis in Monteria city, Colombia.

[Morphological and biochemical features of fungi isolated from patients with renal failure].

PubMed

Drozdowska, Agata

2007-01-01

Patients with renal failure are more frequently at risk of fungal infections than the healthy individuals. The aim of the study was: (1) Evaluation of the prevalence of fungi in biological materials obtained from different ontocenoses from patients with end-stage and chronic renal failure undergoing haemodialysis and conservative treatment, respectively. (2) Species determining of isolated fungal strains and evaluation their morphological and biochemical features with regard to biotyping. (3) Examining the connection between intraspecies features of fungal strains isolated from different ontocenoses of the same patient. The study group comprised 136 persons, including 56 patients with end-stage renal failure dialysed for the mean period of 36.2 (+/- 1.62) months--all patients were on chronic haemodialysis therapy (4 hours sessions, 3 times per week), 50 patients with chronic renal failure undergoing conservative treatment and 30 persons with the negative history of any renal disease--control group. At the moment of the evaluation and collection of samples all patients were in good condition, none of the patients revealed symptoms suggesting possible fungal infection. Material for mycological examinations included washings from the oral cavity and samples of urine and faeces. In order to evaluate morphological and biochemical features of fungi the following methods were applied: (1) macrocultures in solid Sabouraud medium, (2) direct microscopic slides, (3) API 20 C AUX test and (4) API ZYM test (bioMérieux). Totally 385 samples for mycological examinations were collected from different ontocenoses, from which 161 fungal strains were isolated and classified to 17 species from 5 genera. Most strains belonged to the genus Candida 96.9% and the most frequently occurring species was C. albicans (60.3%). Other species from this genus composed 39.7%, among which in 11.8% of cases C. parapsilosis was determined, and the following were: C. guilliermondii and C. humicola--both species isolated in 5.59%, C. glabrata (4.35%), C. rugosa and C. tropicalis (both species were isolated in 2.48%). The remaining isolated fungal strains (3.11 +/- 1.37%) belonged to genera Cryptococcus, Geotrichum, Saccharomyces and Trichosporon. The prevalence of fungi in collected biological materials from chronic dialysed patients, treated conservatively and persons from control group was determined at the level of 96.4%, 64.0% and 63.3%, respectively. In all examined groups fungi were found in high percentage in the ontocenoses of oral cavity and gastrointestinal tract; in dialysed patients (40.7%), treated conservatively (34.4%) and in persons with negative history of any renal disease (42.1%). It should be expressed that in 9.37% of patients with chronic renal failure undergoing conservative treatment fungi were determined at the same time in materials obtained from three ontocenoses--oral cavity, gastrointestinal tract and urinary tract. The majority of C. albicans strains (34.0%) was described by the use of code AUX 2 576 174; code 2 566 174 was found in 23.4% of species. Strains with code AUX 2 576 174 in 96,9% were isolated from chronic haemodialysed patients whereas code 2 566 174 characterized strains (68.2%) obtained from patients treated conservatively. Examined fungal strains from genus Candida obtained from all persons revealed the activity of 10 to 17 enzymes in the API ZYM test. Strains of genus Candida albicans obtained from patients with chronic renal failure treated conservatively and undergoing haemodialysis in majority belonged to biotype A (58.8%) and D3 (40.4%), respectively.

In vitro antifungal susceptibility profiles of Cryptococcus species isolated from HIV-associated cryptococcal meningitis patients in Zimbabwe.

PubMed

Nyazika, Tinashe K; Herkert, Patricia F; Hagen, Ferry; Mateveke, Kudzanai; Robertson, Valerie J; Meis, Jacques F

2016-11-01

Cryptococcus neoformans is the leading cause of cryptococcosis in HIV-infected subjects worldwide. Treatment of cryptococcosis is based on amphotericin B, flucytosine, and fluconazole. In Zimbabwe, little is known about antifungal susceptibility of Cryptococcus. Sixty-eight genotyped Cryptococcus isolates were tested for antifungal profiles. Amphotericin B, isavuconazole, and voriconazole showed higher activity than other triazoles. Fluconazole and flucytosine were less effective, with geometric mean MICs of 2.24 and 2.67mg/L for C. neoformans AFLP1/VNI, 1.38 and 1.53mg/L for C. neoformans AFLP1A/VNB/VNII and AFLP1B/VNII, and 1.85 and 0.68mg/L for Cryptococcus tetragattii, respectively. A significant difference between flucytosine geometric mean MICs of C. neoformans and C. tetragattii was observed (P=0.0002). The majority of isolates (n=66/68; 97.1%) had a wild-type MIC phenotype of all antifungal agents. This study demonstrates a favorable situation with respect to the tested antifungals agents. Continued surveillance of antifungal susceptibility profiles is important due to the high burden of cryptococcosis in Africa. Copyright © 2016 Elsevier Inc. All rights reserved.

Antibiotic-producing bacteria from stag beetle mycangia.

PubMed

Miyashita, Atsushi; Hirai, Yuuki; Sekimizu, Kazuhisa; Kaito, Chikara

2015-02-01

The search for new antibiotics or antifungal agents is crucial for the chemotherapies of infectious diseases. The limited resource of soil bacteria makes it difficult to discover such new drug candidate. We, therefore, focused on another bacterial resource than soil bacteria, the microbial flora of insect species. In the present study, we isolated 40 strains of bacteria and fungi from the mycangia of three species of stag beetle, Dorcus hopei binodulosus, Dorcus rectus, and Dorcus titanus pilifer. We identified those species with their ribosomal DNA sequences, and revealed that Klebsiella spp. are the most frequent symbiont in the stag beetle mycangia. We examined whether these microorganisms produce antibiotics against a Gram-negative bacterium, Escherichia coli, a Gram-positive bacterium, Staphylococcus aureus, or a fungus, Cryptococcus neoformans. Culture supernatants from 33, 29, or 18 strains showed antimicrobial activity against E. coli, S. aureus, or C. neoformans, respectively. These findings suggest that bacteria present in the mycangia of stag beetles are useful resources for screening novel antibiotics.

Sporulation: how to survive on planet Earth (and beyond).

PubMed

Huang, Mingwei; Hull, Christina M

2017-10-01

Sporulation is a strategy widely utilized by a wide variety of organisms to adapt to changes in their individual environmental niches and survive in time and/or space until they encounter conditions acceptable for vegetative growth. The spores produced by bacteria have been the subjects of extensive studies, and several systems such as Bacillus subtilis have provided ample opportunities to understand the molecular basis of spore biogenesis and germination. In contrast, the spores of other microbes, such as fungi, are relatively poorly understood. Studies of sporulation in model systems such as Saccharomyces cerevisiae and Aspergillus nidulans have established a basis for investigating eukaryotic spores, but very little is known at the molecular level about how spores function. This is especially true among the spores of human fungal pathogens such as the most common cause of fatal fungal disease, Cryptococcus neoformans. Recent proteomic studies are helping to determine the molecular mechanisms by which pathogenic fungal spores are formed, persist and germinate into actively growing agents of human disease.

Antimicrobial and antioxidant activities of the methanolic extracts of three Salvia species from Tunisia.

PubMed

Salah, Karima Bel Hadj; Mahjoub, Mohamed Ali; Ammar, Samia; Michel, Laura; Millet-Clerc, Joelle; Chaumont, Jean Pierre; Mighri, Zine; Aouni, Mahjoub

2006-10-01

This study examines the in vitro antimicrobial and antioxidant activities of the methanolic extracts of three Salvia species from Tunisia: Salvia aegyptiaca L., S. argentea L. and S. verbenaca Ssp. clandestina L. Pugsley. The extracts inhibited the growth of dermatophytes and of bacteria responsible for unpleasant odours to varying degrees; the pathogenic yeasts Candida albicans and Cryptococcus neoformans, the filamentous fungi Aspergillus fumigatus and selected dog otitis bacteria were all resistant to each of the extracts. The extracts were screened for their antioxidant activities using 2,2-diphenyl-1-picrylhydrazyl free radical scavenging and 2,2'-azinobis(3-ethylbenzothiazoline-6-sulphonic acid) test systems, and gave positive results in both tests. The extracts of S. aegyptiaca were the most active in both tests, followed by those of S. verbenaca, then S. argentea. These results confirm the antimicrobial and antioxidant activities of the genus Salvia and underline the potential of these plants either as natural preservatives or in pharmaceutical applications.

A multi-criteria analysis approach for ranking and selection of microorganisms for the production of oils for biodiesel production.

PubMed

Ahmad, Farah B; Zhang, Zhanying; Doherty, William O S; O'Hara, Ian M

2015-08-01

Oleaginous microorganisms have potential to be used to produce oils as alternative feedstock for biodiesel production. Microalgae (Chlorella protothecoides and Chlorella zofingiensis), yeasts (Cryptococcus albidus and Rhodotorula mucilaginosa), and fungi (Aspergillus oryzae and Mucor plumbeus) were investigated for their ability to produce oil from glucose, xylose and glycerol. Multi-criteria analysis (MCA) using analytic hierarchy process (AHP) and preference ranking organization method for the enrichment of evaluations (PROMETHEE) with graphical analysis for interactive aid (GAIA), was used to rank and select the preferred microorganisms for oil production for biodiesel application. This was based on a number of criteria viz., oil concentration, content, production rate and yield, substrate consumption rate, fatty acids composition, biomass harvesting and nutrient costs. PROMETHEE selected A. oryzae, M. plumbeus and R. mucilaginosa as the most prospective species for oil production. However, further analysis by GAIA Webs identified A. oryzae and M. plumbeus as the best performing microorganisms. Copyright © 2015 Elsevier Ltd. All rights reserved.

Forum of Microbial Threats

DTIC Science & Technology

2011-06-01

Cryptococcus gattii, a pathogenic environmental fungus believed to have been introduced onto Vancouver Island, British Columbia, Canada in 1999, is...factors‖ others such as Crytococcus gattii, are emerging with altered virulence and geographic ranges. Cryptococcus gattii, a pathogenic environmental

Cryptococcus spp isolated from dust microhabitat in Brazilian libraries.

PubMed

Leite, Diniz P; Amadio, Janaina V R S; Martins, Evelin R; Simões, Sara A A; Yamamoto, Ana Caroline A; Leal-Santos, Fábio A; Takahara, Doracilde T; Hahn, Rosane C

2012-06-08

The Cryptococcus spp is currently composed of encapsulated yeasts of cosmopolitan distribution, including the etiological agents of cryptococcosis. The fungus are found mainly in substrates of animal and plant origin. Human infection occurs through inhalation of spores present in the environment. Eighty-four swab collections were performed on dust found on books in three libraries in the city of Cuiabá, state of Mato Grosso, Brazil. The material was seeded in Sabouraud agar and then observed for characteristics compatible with colonies with a creamy to mucous aspect; the material was then isolated in birdseed (Niger) agar and cultivated at a temperature of 37°C for 5 to 7 days. Identification of isolated colonies was performed by microscopic observation in fresh preparations dyed with India ink, additional tests performed on CGB (L-canavanine glycine bromothymol blue), urea broth, and carbohydrate assimilation tests (auxanogram). Of the 84 samples collected from book dust, 18 (21.4%) were positive for Cryptococcus spp totalizing 41 UFC's. The most frequently isolated species was C. gattii 15 (36.6%); followed by C. terreus, 12 (29.3%); C. luteolus 4 (9.8%); C. neoformans, and C. uniguttulatus 3 (7.3%), and C. albidus and C. humiculus with 2 (4.6%) of the isolates. The high biodiversity of the yeasts of the Cryptococcus genus, isolated from different environmental sources in urban areas of Brazil suggests the possibility of individuals whose immune systems have been compromised or even healthy individuals coming into sources of fungal propagules on a daily bases throughout their lives. This study demonstrates the acquisition possible of cryptococcosis infection from dust in libraries.

Molecular characterization and antifungal susceptibility of Cryptococcus neoformans strains collected from a single institution in Lima, Peru.

PubMed

Bejar, Vilma; Tello, Mercedes; García, Ruth; Guevara, José M; Gonzales, Sofia; Vergaray, German; Valencia, Esther; Abanto, Enma; Ortega-Loayza, Alex G; Hagen, Ferry; Gutierrez, Ericson L

2015-01-01

Cryptococcosis is a fungal infection with a worldwide distribution, mainly caused by Cryptococcus neoformans and Cryptococcus gattii. To molecularly characterize the mating-types, serotypes, genotypes and antifungal susceptibility profiles of a set of retrospectively isolated C. neoformans strains from Lima, Peru. A set of 32 Cryptococcus spp. strains from the Institute of Tropical Medicine of the National University of San Marcos, Lima, Peru, were included in this retrospective study. Twenty-four strains were isolated from patients, while the remaining 8 were isolated from the environment. Using conventional PCR, 27 (84.4%) of the isolates were identified as C. neoformans var. grubii mating-type alpha and serotype A. Using the AFLP fingerprinting, it was shown that 16 (50%) of the C. neoformans strains were genotype AFLP1, 13 (40.6%) were genotype AFLP1B, 2 (6.3%) were genotype AFLP2, and 1 (3.1%) was found to be a hybrid between both C. neoformans varieties (genotype AFLP3). The antifungal susceptibility profiles for amphotericin B, fluconazole and voriconazole showed that all the 32 C. neoformans are sensitive to these antifungal compounds. In this study we observed that C. neoformans var. grubii (AFLP1 and AFLP1B) and C. neoformans var. neoformans (AFLP2) were the only cryptococcal varieties involved. All strains were found to be sensitive to the antifungals tested, results that are consistent with those found in the international literature. Copyright © 2013 Revista Iberoamericana de Micología. Published by Elsevier Espana. All rights reserved.

Novel Gbeta Mimic Kelch Proteins (Gpb1 and Gpb2 Connect G-Protein Signaling to Ras via Yeast Neurofibromin Homologs Ira1 and Ira2. A Model for Human NF1

DTIC Science & Technology

2007-03-01

Saccharomyces cerevisiae and model fungus Cryptococcus neoformans as models to understand how the GAP activity of the yeast neurofibromin homologs, Ira1...another genetically tractable fungal model system, Cryptococcus neoformans, and identified two kelch repeat homologs that are involved in mating (Kem1 and...Kem2). To find kelch-repeat proteins involved in G protein signaling, Cryptococcus homologues of Gpb1/2, which interacts with and negatively

Novel Gbeta Mimic Kelch Proteins (Gpb1 and Gpb2 Connect G-Protein Signaling to Ras via Yeast Neurofibromin Homologs Ira1 and Ira2: A Model for Human NF1

DTIC Science & Technology

2008-03-01

tractable fungal model system, Cryptococcus neoformans, and identified two kelch repeat homologs that are involved in mating (Kem1 and Kem2). To...find kelch-repeat proteins involved in G protein signaling, Cryptococcus homologues of Gpb1/2, which interacts with and negatively regulates the G...protein alpha subunit, Gpa2, in S. cerevisiae, were searched by BLAST (tblastn) in Cryptococcus genome database of serotype A (Duke University Medical

Phylogenetic analysis of phenotypically characterized Cryptococcus laurentii isolates reveals high frequency of cryptic species.

PubMed

Ferreira-Paim, Kennio; Ferreira, Thatiana Bragine; Andrade-Silva, Leonardo; Mora, Delio Jose; Springer, Deborah J; Heitman, Joseph; Fonseca, Fernanda Machado; Matos, Dulcilena; Melhem, Márcia Souza Carvalho; Silva-Vergara, Mario León

2014-01-01

Although Cryptococcus laurentii has been considered saprophytic and its taxonomy is still being described, several cases of human infections have already reported. This study aimed to evaluate molecular aspects of C. laurentii isolates from Brazil, Botswana, Canada, and the United States. In this study, 100 phenotypically identified C. laurentii isolates were evaluated by sequencing the 18S nuclear ribosomal small subunit rRNA gene (18S-SSU), D1/D2 region of 28S nuclear ribosomal large subunit rRNA gene (28S-LSU), and the internal transcribed spacer (ITS) of the ribosomal region. BLAST searches using 550-bp, 650-bp, and 550-bp sequenced amplicons obtained from the 18S-SSU, 28S-LSU, and the ITS region led to the identification of 75 C. laurentii strains that shared 99-100% identity with C. laurentii CBS 139. A total of nine isolates shared 99% identity with both Bullera sp. VY-68 and C. laurentii RY1. One isolate shared 99% identity with Cryptococcus rajasthanensis CBS 10406, and eight isolates shared 100% identity with Cryptococcus sp. APSS 862 according to the 28S-LSU and ITS regions and designated as Cryptococcus aspenensis sp. nov. (CBS 13867). While 16 isolates shared 99% identity with Cryptococcus flavescens CBS 942 according to the 18S-SSU sequence, only six were confirmed using the 28S-LSU and ITS region sequences. The remaining 10 shared 99% identity with Cryptococcus terrestris CBS 10810, which was recently described in Brazil. Through concatenated sequence analyses, seven sequence types in C. laurentii, three in C. flavescens, one in C. terrestris, and one in the C. aspenensis sp. nov. were identified. Sequencing permitted the characterization of 75% of the environmental C. laurentii isolates from different geographical areas and the identification of seven haplotypes of this species. Among sequenced regions, the increased variability of the ITS region in comparison to the 18S-SSU and 28S-LSU regions reinforces its applicability as a DNA barcode.

Cytoplasmic inorganic polyphosphate participates in the heavy metal tolerance of Cryptococcus humicola.

PubMed

Andreeva, Nadezhda; Ryazanova, Lubov; Dmitriev, Vladimir; Kulakovskaya, Tatiana; Kulaev, Igor

2014-09-01

The basidiomycetous yeast Cryptococcus humicola was shown to be tolerant to manganese, cobalt, nickel, zinc, lanthanum, and cadmium cations at a concentration of 2.5 mmol/L, which is toxic for many yeasts. The basidiomycetous yeast Cryptococcus terreus was sensitive to all these ions and did not grow at the above concentration. In the presence of heavy metal cations, С. humicola, as opposed to C. terreus, was characterized by the higher content of acid-soluble inorganic polyphosphates. In vivo 4',6'-diamino-2-phenylindole dihydrochloride staining revealed polyphosphate accumulation in the cell wall and cytoplasmic inclusions of С. humicola in the presence of heavy metals. In C. terreus, polyphosphates in the presence of heavy metals accumulate mainly in vacuoles, which results in morphological changes in these organelles and, probably, disturbance of their function. The role of polyphosphate accumulation and cellular localization as factors of heavy metal tolerance of Cryptococcus humicola is discussed.

In vitro C3 Deposition on Cryptococcus Capsule Occurs Via Multiple Complement Activation Pathways

PubMed Central

Mershon-Shier, Kileen L.; Vasuthasawat, Alex; Takahashi, Kazue; Morrison, Sherie L.; Beenhouwer, David O.

2011-01-01

Complement can be activated via three pathways: classical, alternative, and lectin. Cryptococcus gattii and C. neoformans are closely related fungal pathogens possessing a polysaccharide capsule composed mainly of glucuronoxylomannan (GXM), which serves as a site for complement activation and deposition of complement components. We determined C3 deposition on Cryptococcus spp. by flow cytometry and confocal microscopy after incubation with serum from C57BL/6J mice as well as mice deficient in complement components C4, C3, factor B, and mannose binding lectin (MBL). C. gattii and C. neoformans activate complement in EGTA-treated serum indicating that they can activate the alternative pathway. However, complement activation was seen with factor B−/− serum suggesting activation could also take place in the absence of a functional alternative pathway. Furthermore, we uncovered a role for C4 in the alternative pathway activation by Cryptococcus spp. We also identified an unexpected and complex role for MBL in complement activation by Cryptococcus spp. No complement activation occurred in the absence of MBL-A and -C proteins although activation took place when the lectin binding activity of MBL was disrupted by calcium chelation. In addition, alternative pathway activation by C. neoformans required both MBL-A and -C, while either MBL-A or -C was sufficient for alternative pathway activation by C. gattii. Thus, complement activation by Cryptococcus spp. can take place through multiple pathways and complement activation via the alternative pathway requires the presence of C4 and MBL proteins. PMID:21723612

Miltefosine has post-antifungal effect and induces apoptosis in Cryptococcus yeasts.

PubMed

Spadari, Cristina de Castro; Vila, Taissa; Rozental, Sonia; Ishida, Kelly

2018-05-29

Cryptococcus spp. are common opportunistic fungal pathogens, particularly in HIV patients. The approved drug miltefosine (MFS) has potential as an alternative antifungal against cryptococcosis; however, the mechanism of action of MFS in Cryptococcus is poorly understood. Here, we examined the effects of MFS on C. neoformans and C. gattii yeasts (planktonic and biofilm lifestyles), to clarify its mechanism of action. MFS presented inhibitory and fungicidal effects against planktonic Cryptococcus cells, with similar activity against dispersion biofilm cells, while sessile biofilm cells were less sensitive to MFS. Interestingly, MFS had post-antifungal effect on Cryptococcus , with a proliferation delay of up to 8.15 h after short exposure to fungicidal doses. MFS at fungicidal concentrations increased plasma membrane permeability, likely due to direct interaction with ergosterol, as suggested by competition assays with exogenous ergosterol. Moreover, MFS reduced the mitochondrial membrane potential, increased ROS production, and induced DNA fragmentation and condensation, all of which are hallmarks of apoptosis. Transmission electron microscopy analysis showed that MFS-treated yeasts had a reduced mucopolysaccharide capsule (confirmed by morphometry in light microscopy), plasma membrane irregularities, mitochondrial swelling and a less conspicuous cell wall. Our results suggest that MFS increases plasma membrane permeability in Cryptococcus via interaction with ergosterol, and also affects the mitochondrial membrane, eventually leading to apoptosis, in line with its fungicidal activity. These findings confirm the potential of MFS as an antifungal against C. neoformans and C. gattii, and warrants further studies to establish clinical protocols for MFS use against cryptococcosis. Copyright © 2018 American Society for Microbiology.

Correlation of Culture with Histopathology in Fungal Burn Wound Colonization and Infection

DTIC Science & Technology

2007-01-01

Echinocandin Anidulafungin, caspofungin, micafungin Candidal yeasts and Aspergillus Zygomycetes, Cryptococcus , Trichosporon, Fusarium Candida...less common moulds, as well as Cryptococcus and Trichosporon species. Of the currently approved agents, only amphotericin B has proven efficacy

Fungal genome and mating system transitions facilitated by chromosomal translocations involving intercentromeric recombination

PubMed Central

Yadav, Vikas; Billmyre, R. Blake; Cuomo, Christina A.; Nowrousian, Minou; Wang, Liuyang; Souciet, Jean-Luc; Boekhout, Teun; Porcel, Betina; Wincker, Patrick; Granek, Joshua A.; Sanyal, Kaustuv; Heitman, Joseph

2017-01-01

Species within the human pathogenic Cryptococcus species complex are major threats to public health, causing approximately 1 million annual infections globally. Cryptococcus amylolentus is the most closely known related species of the pathogenic Cryptococcus species complex, and it is non-pathogenic. Additionally, while pathogenic Cryptococcus species have bipolar mating systems with a single large mating type (MAT) locus that represents a derived state in Basidiomycetes, C. amylolentus has a tetrapolar mating system with 2 MAT loci (P/R and HD) located on different chromosomes. Thus, studying C. amylolentus will shed light on the transition from tetrapolar to bipolar mating systems in the pathogenic Cryptococcus species, as well as its possible link with the origin and evolution of pathogenesis. In this study, we sequenced, assembled, and annotated the genomes of 2 C. amylolentus isolates, CBS6039 and CBS6273, which are sexual and interfertile. Genome comparison between the 2 C. amylolentus isolates identified the boundaries and the complete gene contents of the P/R and HD MAT loci. Bioinformatic and chromatin immunoprecipitation sequencing (ChIP-seq) analyses revealed that, similar to those of the pathogenic Cryptococcus species, C. amylolentus has regional centromeres (CENs) that are enriched with species-specific transposable and repetitive DNA elements. Additionally, we found that while neither the P/R nor the HD locus is physically closely linked to its centromere in C. amylolentus, and the regions between the MAT loci and their respective centromeres show overall synteny between the 2 genomes, both MAT loci exhibit genetic linkage to their respective centromere during meiosis, suggesting the presence of recombinational suppressors and/or epistatic gene interactions in the MAT-CEN intervening regions. Furthermore, genomic comparisons between C. amylolentus and related pathogenic Cryptococcus species provide evidence that multiple chromosomal rearrangements mediated by intercentromeric recombination have occurred during descent of the 2 lineages from their common ancestor. Taken together, our findings support a model in which the evolution of the bipolar mating system was initiated by an ectopic recombination event mediated by similar repetitive centromeric DNA elements shared between chromosomes. This translocation brought the P/R and HD loci onto the same chromosome, and further chromosomal rearrangements then resulted in the 2 MAT loci becoming physically linked and eventually fusing to form the single contiguous MAT locus that is now extant in the pathogenic Cryptococcus species. PMID:28800596

Development of non-natural flavanones as antimicrobial agents.

PubMed

Fowler, Zachary L; Shah, Karan; Panepinto, John C; Jacobs, Amy; Koffas, Mattheos A G

2011-01-01

With growing concerns over multidrug resistance microorganisms, particularly strains of bacteria and fungi, evolving to become resistant to the antimicrobial agents used against them, the identification of new molecular targets becomes paramount for novel treatment options. Recently, the use of new treatments containing multiple active ingredients has been shown to increase the effectiveness of existing molecules for some infections, often with these added compounds enabling the transport of a toxic molecule into the infecting species. Flavonoids are among the most abundant plant secondary metabolites and have been shown to have natural abilities as microbial deterrents and anti-infection agents in plants. Combining these ideas we first sought to investigate the potency of natural flavonoids in the presence of efflux pump inhibitors to limit Escherichia coli growth. Then we used the natural flavonoid scaffold to synthesize non-natural flavanone molecules and further evaluate their antimicrobial efficacy on Escherichia coli, Bacillus subtilis and the fungal pathogens Cryptococcus neoformans and Aspergillus fumigatus. Of those screened, we identified the synthetic molecule 4-chloro-flavanone as the most potent antimicrobial compound with a MIC value of 70 µg/mL in E. coli when combined with the inhibitor Phe-Arg-ß-naphthylamide, and MICs of 30 µg/mL in S. cerevesiae and 30 µg/mL in C. neoformans when used alone. Through this study we have demonstrated that combinatorial synthesis of non-natural flavonones can identify novel antimicrobial agents with activity against bacteria and fungi but with minimal toxicity to human cells.

Occurrence of Dermatophytes in Fresh Bat Guano1

PubMed Central

Kajihiro, Edwin S.

1965-01-01

Evidence is presented in support of the hypothesis that fresh bat guano serves as a means of pathogenic fungi dissemination in caves. A total of 371 guano samples were collected from caves in southeastern New Mexico. Each sample was agitated in sterile saline and sand. The supernatant fluid was treated with an antibiotic and streaked on differential media. Cultures were incubated at 25 and 37 C and examined at intervals over a 4-week period. For animal inoculation, highly concentrated inoculum was injected intraperitoneally into white Swiss mice. Animals were sacrificed 4 weeks later, and portions of their lung, liver, and spleen were cultured on selective media, incubated at 25 C, and examined at intervals over a 4-week period. Microsporum gypseum was isolated at all 10 collecting stations with an incidence of 22.4%, Trichophyton mentagrophytes at 7 stations with an incidence of 5%, T. rubrum at 3 stations with an incidence of 3%, and T. terrestre at 1 station with an incidence of 0.5%. From a total of 60 pools of liver-spleen-lung suspensions, 6 pools yielded positive cultures of Histoplasma capsulatum and 1 pool yielded T. mentagrophytes. No significant difference was found among the different selective media with respect to recovery of dermatophytes. Among the human pathogenic fungi isolated were Candida sp., Cladosporium sp., Coccidioides immitis, Cryptococcus neoformans, H. capsulatum, M. gypseum, T. mentagrophytes, T. rubrum, T. terrestre, and Sporotrichum sp. Images Fig. 1 PMID:5867652

Development of Non-Natural Flavanones as Antimicrobial Agents

PubMed Central

Fowler, Zachary L.; Shah, Karan; Panepinto, John C.; Jacobs, Amy; Koffas, Mattheos A. G.

2011-01-01

With growing concerns over multidrug resistance microorganisms, particularly strains of bacteria and fungi, evolving to become resistant to the antimicrobial agents used against them, the identification of new molecular targets becomes paramount for novel treatment options. Recently, the use of new treatments containing multiple active ingredients has been shown to increase the effectiveness of existing molecules for some infections, often with these added compounds enabling the transport of a toxic molecule into the infecting species. Flavonoids are among the most abundant plant secondary metabolites and have been shown to have natural abilities as microbial deterrents and anti-infection agents in plants. Combining these ideas we first sought to investigate the potency of natural flavonoids in the presence of efflux pump inhibitors to limit Escherichia coli growth. Then we used the natural flavonoid scaffold to synthesize non-natural flavanone molecules and further evaluate their antimicrobial efficacy on Escherichia coli, Bacillus subtilis and the fungal pathogens Cryptococcus neoformans and Aspergillus fumigatus. Of those screened, we identified the synthetic molecule 4-chloro-flavanone as the most potent antimicrobial compound with a MIC value of 70 µg/mL in E. coli when combined with the inhibitor Phe-Arg-ß-naphthylamide, and MICs of 30 µg/mL in S. cerevesiae and 30 µg/mL in C. neoformans when used alone. Through this study we have demonstrated that combinatorial synthesis of non-natural flavonones can identify novel antimicrobial agents with activity against bacteria and fungi but with minimal toxicity to human cells. PMID:22039419

Synthesis of natural acylphloroglucinol-based antifungal compounds against Cryptococcus species

USDA-ARS?s Scientific Manuscript database

Thirty-five analogs of naturally occurring acylphloroglucinols were designed and synthesized to identify antifungal compounds against Cryptococcus spp. that causes the life-threatening disseminated cryptococcosis. In vitro antifungal testing showed that 17 compounds were active against C. neoformans...

Cryptococcus Neoformans in Pigeon Feces in San Francisco

PubMed Central

Halde, Carlyn; Fraher, Margaret Anne

1966-01-01

Typical Cryptococcus neoformans was isolated from one of 10 specimens of pigeon feces collected in downtown San Francisco. This isolation from a small sample suggests considerable prevalence of this important pathogen and tends to confirm that it is ubiquitous. PMID:5936987

Cryptococcus laurentii fungaemia in a cervical cancer patient.

PubMed

Neves, Rejane Pereira; Lima Neto, Reginaldo Gonçalves de; Leite, Melyna Chaves; Silva, Vanessa Karina Alves da; Santos, Franz de Assis Graciano dos; Macêdo, Danielle Patrícia Cerqueira

2015-01-01

Infections caused by emerging Cryptococcus non-neoformans species are being reported with increasingly frequency. Here, we present a case of fungaemia by Cryptococcus laurentii in a woman receiving aggressive immunosuppressive therapy for cervical neoplasia. Three venous blood samples were aseptically collected on consecutive days and C. laurentii was isolated and identified through phenotypic and molecular methods. After central venous catheter removal and appropriate antifungal therapy, the patient showed significant improvement and blood culture became negative. Thus, patients following immunosuppressive therapies and using invasive medical devices are at risk of C. laurentii blood infections. Copyright © 2015 Elsevier Editora Ltda. All rights reserved.

Expression of a chitin deacetylase gene, up-regulated in Cryptococcus laurentii strain RY1, under nitrogen limitation.

PubMed

Chakraborty, Writachit; Sarkar, Soumyadev; Chakravorty, Somnath; Bhattacharya, Semantee; Bhattacharya, Debanjana; Gachhui, Ratan

2016-05-01

This study reports the identification of a chitin deacetylase gene in Cryptococcus laurentii strain RY1 over-expressing under nitrogen limitation by differential display. The up-regulation took place in robustly growing cells rather than in starving quiescent autophagic cells. Quantitative Real Time-PCR, enzyme activity in cell lysate and cell wall analysis corroborated the up-regulation of chitin deacetylase under nitrogen limitation. These results suggest chitin deacetylase might play a significant role in nitrogen limiting growth of Cryptococcus laurentii strain RY1. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Comparison of biotyping methods as alternative identification tools to molecular typing of pathogenic Cryptococcus species in sub-Saharan Africa.

PubMed

Nyazika, Tinashe K; Robertson, Valerie J; Nherera, Brenda; Mapondera, Prichard T; Meis, Jacques F; Hagen, Ferry

2016-03-01

Cryptococcal meningitis is the leading fungal infection and AIDS defining opportunistic illness in patients with late stage HIV infection, particularly in South-East Asia and sub-Saharan Africa. Given the high mortality, clinical differences and the extensive ecological niche of Cryptococcus neoformans and Cryptococcus gattii species complexes, there is need for laboratories in sub-Sahara African countries to adopt new and alternative reliable diagnostic algorithms that rapidly identify and distinguish these species. We biotyped 74 and then amplified fragment length polymorphism (AFLP) genotyped 66 Cryptococcus isolates from a cohort of patients with HIV-associated cryptococcal meningitis. C. gattii sensu lato was isolated at a prevalence of 16.7% (n = 11/66) and C. neoformans sensu stricto was responsible for 83.3% (n = 55/66) of the infections. l-Canavanine glycine bromothymol blue, yeast-carbon-base-d-proline-d-tryptophan and creatinine dextrose bromothymol blue thymine were able to distinguish pathogenic C. gattii sensu lato from C. neoformans sensu stricto species when compared with AFLP genotyping. This study demonstrates high C. gattii sensu lato prevalence in Zimbabwe. In addition, biotyping methods can be used as alternative diagnostic tools to molecular typing in resource-limited areas for differentiating pathogenic Cryptococcus species. © 2015 Blackwell Verlag GmbH.

Growth of high-elevation Cryptococcus sp. during extreme freeze-thaw cycles.

PubMed

Vimercati, L; Hamsher, S; Schubert, Z; Schmidt, S K

2016-09-01

Soils above 6000 m.a.s.l. are among the most extreme environments on Earth, especially on high, dry volcanoes where soil temperatures cycle between -10 and 30 °C on a typical summer day. Previous studies have shown that such sites are dominated by yeast in the cryophilic Cryptococcus group, but it is unclear if they can actually grow (or are just surviving) under extreme freeze-thaw conditions. We carried out a series of experiments to determine if Cryptococcus could grow during freeze-thaw cycles similar to those measured under field conditions. We found that Cryptococcus phylotypes increased in relative abundance in soils subjected to 48 days of freeze-thaw cycles, becoming the dominant organisms in the soil. In addition, pure cultures of Cryptococcus isolated from these same soils were able to grow in liquid cultures subjected to daily freeze-thaw cycles, despite the fact that the culture medium froze solid every night. Furthermore, we showed that this organism is metabolically versatile and phylogenetically almost identical to strains from Antarctic Dry Valley soils. Taken together these results indicate that this organism has unique metabolic and temperature adaptations that make it able to thrive in one of the harshest and climatically volatile places on Earth.

De novo GTP Biosynthesis Is Critical for Virulence of the Fungal Pathogen Cryptococcus neoformans

PubMed Central

Morrow, Carl A.; Valkov, Eugene; Stamp, Anna; Chow, Eve W. L.; Lee, I. Russel; Wronski, Ania; Williams, Simon J.; Hill, Justine M.; Djordjevic, Julianne T.; Kappler, Ulrike; Kobe, Bostjan; Fraser, James A.

2012-01-01

We have investigated the potential of the GTP synthesis pathways as chemotherapeutic targets in the human pathogen Cryptococcus neoformans, a common cause of fatal fungal meningoencephalitis. We find that de novo GTP biosynthesis, but not the alternate salvage pathway, is critical to cryptococcal dissemination and survival in vivo. Loss of inosine monophosphate dehydrogenase (IMPDH) in the de novo pathway results in slow growth and virulence factor defects, while loss of the cognate phosphoribosyltransferase in the salvage pathway yielded no phenotypes. Further, the Cryptococcus species complex displays variable sensitivity to the IMPDH inhibitor mycophenolic acid, and we uncover a rare drug-resistant subtype of C. gattii that suggests an adaptive response to microbial IMPDH inhibitors in its environmental niche. We report the structural and functional characterization of IMPDH from Cryptococcus, revealing insights into the basis for drug resistance and suggesting strategies for the development of fungal-specific inhibitors. The crystal structure reveals the position of the IMPDH moveable flap and catalytic arginine in the open conformation for the first time, plus unique, exploitable differences in the highly conserved active site. Treatment with mycophenolic acid led to significantly increased survival times in a nematode model, validating de novo GTP biosynthesis as an antifungal target in Cryptococcus. PMID:23071437

New secondary metabolites from bioactive extracts of the fungus Armillaria tabescens

USDA-ARS?s Scientific Manuscript database

Ethyl acetate extracts of Armillaria tabescens (strain JNB-OZ344) mycelium showed significant fungistatic and bacteristatic activities against several major human pathogens including Candida albicans, Cryptococcus neoformans, Escherichia coli and Mycobacterium intracellulare. Chemical analysis of th...

GROWTH INHIBITION OF 'CRYPTOCOCCUS NEOFORMANS' BY HUMAN ALVEOLAR MACROPHAGES (JOURNAL VERSION)

EPA Science Inventory

Macrophage cytotoxicity for Cryptococcus neoformans was investigated by culturing human alveolar macrophage (AM) with a thin-capsuled clone of C. neoformans. Under appropriate conditions, fungal replication was inhibited in the presence of human AM. The effect persisted over the ...

Vaccination with Recombinant Cryptococcus Proteins in Glucan Particles Protects Mice against Cryptococcosis in a Manner Dependent upon Mouse Strain and Cryptococcal Species

PubMed Central

Lee, Chrono K.; Huang, Haibin; Hester, Maureen M.; Liu, Jianhua; Luckie, Bridget A.; Torres Santana, Melanie A.; Mirza, Zeynep; Khoshkenar, Payam; Abraham, Ambily; Shen, Zu T.; Lodge, Jennifer K.; Akalin, Ali; Homan, Jane; Ostroff, Gary R.

2017-01-01

ABSTRACT Development of a vaccine to protect against cryptococcosis is a priority given the enormous global burden of disease in at-risk individuals. Using glucan particles (GPs) as a delivery system, we previously demonstrated that mice vaccinated with crude Cryptococcus-derived alkaline extracts were protected against lethal challenge with Cryptococcus neoformans and Cryptococcus gattii. The goal of the present study was to identify protective protein antigens that could be used in a subunit vaccine. Using biased and unbiased approaches, six candidate antigens (Cda1, Cda2, Cda3, Fpd1, MP88, and Sod1) were selected, recombinantly expressed in Escherichia coli, purified, and loaded into GPs. Three mouse strains (C57BL/6, BALB/c, and DR4) were then vaccinated with the antigen-laden GPs, following which they received a pulmonary challenge with virulent C. neoformans and C. gattii strains. Four candidate vaccines (GP-Cda1, GP-Cda2, GP-Cda3, and GP-Sod1) afforded a significant survival advantage in at least one mouse model; some vaccine combinations provided added protection over that seen with either antigen alone. Vaccine-mediated protection against C. neoformans did not necessarily predict protection against C. gattii. Vaccinated mice developed pulmonary inflammatory responses that effectively contained the infection; many surviving mice developed sterilizing immunity. Predicted T helper cell epitopes differed between mouse strains and in the degree to which they matched epitopes predicted in humans. Thus, we have discovered cryptococcal proteins that make promising candidate vaccine antigens. Protection varied depending on the mouse strain and cryptococcal species, suggesting that a successful human subunit vaccine will need to contain multiple antigens, including ones that are species specific. PMID:29184017

Population Genetic Analysis Reveals a High Genetic Diversity in the Brazilian Cryptococcus gattii VGII Population and Shifts the Global Origin from the Amazon Rainforest to the Semi-arid Desert in the Northeast of Brazil.

PubMed

Souto, Ana C P; Bonfietti, Lucas X; Ferreira-Paim, Kennio; Trilles, Luciana; Martins, Marilena; Ribeiro-Alves, Marcelo; Pham, Cau D; Martins, Liline; Dos Santos, Wallace; Chang, Marilene; Brito-Santos, Fabio; Santos, Dayane C S; Fortes, Silvana; Lockhart, Shawn R; Wanke, Bodo; Melhem, Márcia S C; Lazéra, Márcia S; Meyer, Wieland

2016-08-01

Cryptococcus neoformans and Cryptococcus gattii are responsible globally for almost one million cryptococcosis cases yearly, mostly in immunocompromised patients, such as those living with HIV. Infections due to C. gattii have mainly been described in tropical and subtropical regions, but its adaptation to temperate regions was crucial in the species evolution and highlighted the importance of this pathogenic yeast in the context of disease. Cryptococcus gattii molecular type VGII has come to the forefront in connection with an on-going emergence in the Pacific North West of North America. Taking into account that previous work pointed towards South America as an origin of this species, the present work aimed to assess the genetic diversity within the Brazilian C. gattii VGII population in order to gain new insights into its origin and global dispersal from the South American continent using the ISHAM consensus MLST typing scheme. Our results corroborate the finding that the Brazilian C. gattii VGII population is highly diverse. The diversity is likely due to recombination generated from sexual reproduction, as evidenced by the presence of both mating types in clinical and environmental samples. The data presented herein strongly supports the emergence of highly virulent strains from ancestors in the Northern regions of Brazil, Amazonia and the Northeast. Numerous genotypes represent a link between Brazil and other parts of the world reinforcing South America as the most likely origin of the C. gattii VGII subtypes and their subsequent global spread, including their dispersal into North America, where they caused a major emergence.

A Unique Chromosomal Rearrangement in the Cryptococcus neoformans var. grubii Type Strain Enhances Key Phenotypes Associated with Virulence

PubMed Central

Morrow, Carl A.; Lee, I. Russel; Chow, Eve W. L.; Ormerod, Kate L.; Goldinger, Anita; Byrnes, Edmond J.; Nielsen, Kirsten; Heitman, Joseph; Schirra, Horst Joachim; Fraser, James A.

2012-01-01

ABSTRACT The accumulation of genomic structural variation between closely related populations over time can lead to reproductive isolation and speciation. The fungal pathogen Cryptococcus is thought to have recently diversified, forming a species complex containing members with distinct morphologies, distributions, and pathologies of infection. We have investigated structural changes in genomic architecture such as inversions and translocations that distinguish the most pathogenic variety, Cryptococcus neoformans var. grubii, from the less clinically prevalent Cryptococcus neoformans var. neoformans and Cryptococcus gattii. Synteny analysis between the genomes of the three Cryptococcus species/varieties (strains H99, JEC21, and R265) reveals that C. neoformans var. grubii possesses surprisingly few unique genomic rearrangements. All but one are relatively small and are shared by all molecular subtypes of C. neoformans var. grubii. In contrast, the large translocation peculiar to the C. neoformans var. grubii type strain is found in all tested subcultures from multiple laboratories, suggesting that it has possessed this rearrangement since its isolation from a human clinical sample. Furthermore, we find that the translocation directly disrupts two genes. The first of these encodes a novel protein involved in metabolism of glucose at human body temperature and affects intracellular levels of trehalose. The second encodes a homeodomain-containing transcription factor that modulates melanin production. Both mutations would be predicted to increase pathogenicity; however, when recreated in an alternate genetic background, these mutations do not affect virulence in animal models. The type strain of C. neoformans var. grubii in which the majority of molecular studies have been performed is therefore atypical for carbon metabolism and key virulence attributes. PMID:22375073

Genome Evolution and Innovation across the Four Major Lineages of Cryptococcus gattii.

PubMed

Farrer, Rhys A; Desjardins, Christopher A; Sakthikumar, Sharadha; Gujja, Sharvari; Saif, Sakina; Zeng, Qiandong; Chen, Yuan; Voelz, Kerstin; Heitman, Joseph; May, Robin C; Fisher, Matthew C; Cuomo, Christina A

2015-09-01

Cryptococcus gattii is a fungal pathogen of humans, causing pulmonary infections in otherwise healthy hosts. To characterize genomic variation among the four major lineages of C. gattii (VGI, -II, -III, and -IV), we generated, annotated, and compared 16 de novo genome assemblies, including the first for the rarely isolated lineages VGIII and VGIV. By identifying syntenic regions across assemblies, we found 15 structural rearrangements, which were almost exclusive to the VGI-III-IV lineages. Using synteny to inform orthology prediction, we identified a core set of 87% of C. gattii genes present as single copies in all four lineages. Remarkably, 737 genes are variably inherited across lineages and are overrepresented for response to oxidative stress, mitochondrial import, and metal binding and transport. Specifically, VGI has an expanded set of iron-binding genes thought to be important to the virulence of Cryptococcus, while VGII has expansions in the stress-related heat shock proteins relative to the other lineages. We also characterized genes uniquely absent in each lineage, including a copper transporter absent from VGIV, which influences Cryptococcus survival during pulmonary infection and the onset of meningoencephalitis. Through inclusion of population-level data for an additional 37 isolates, we identified a new transcontinental clonal group that we name VGIIx, mitochondrial recombination between VGII and VGIII, and positive selection of multidrug transporters and the iron-sulfur protein aconitase along multiple branches of the phylogenetic tree. Our results suggest that gene expansion or contraction and positive selection have introduced substantial variation with links to mechanisms of pathogenicity across this species complex. The genetic differences between phenotypically different pathogens provide clues to the underlying mechanisms of those traits and can lead to new drug targets and improved treatments for those diseases. In this paper, we compare 16 genomes belonging to four highly differentiated lineages of Cryptococcus gattii, which cause pulmonary infections in otherwise healthy humans and other animals. Half of these lineages have not had their genomes previously assembled and annotated. We identified 15 ancestral rearrangements in the genome and over 700 genes that are unique to one or more lineages, many of which are associated with virulence. In addition, we found evidence for recent transcontinental spread, mitochondrial genetic exchange, and positive selection in multidrug transporters. Our results suggest that gene expansion/contraction and positive selection are diversifying the mechanisms of pathogenicity across this species complex. Copyright © 2015 Farrer et al.

Cryptococcus gattii infection in a Spanish pet ferret (Mustela putorius furo) and asymptomatic carriage in ferrets and humans from its environment.

PubMed

Morera, Neus; Juan-Sallés, Carles; Torres, Josep M; Andreu, Mariano; Sánchez, Manuel; Zamora, María Ángeles; Colom, M Francisca

2011-10-01

A domestic ferret (Mustela putorius furo) was presented with lymphadenopathy and acute bilateral blindness. Cytologic evaluation and biopsy of an affected lymph node revealed pyogranulomatous lymphadenitis with intralesional yeast consistent with Cryptococcus sp. Subsequent studies demonstrated Cryptococcus gattii serotype B VGI/AFLP4 as the causative agent. The ferret was treated with fluconazole and prednisone. After one month of therapy, an improvement of the clinical symptoms was detected although blindness persisted. Seven months after presentation, the disease progressed to a severe neurologic condition, and it was euthanized. Postmortem exam revealed disseminated cryptococcosis with prominent neurologic involvement. Nasal swabs of other ferrets and humans from the same household revealed that two ferrets and two humans to be asymptomatic carriers of the same strain of cryptococcus as the necropsied ferret. These findings stress the importance of veterinary diagnostic work with pets and epidemiological investigations for disease prevention in them and in their owners.

Evaluation of SOC for the presumptive identification of Candida albicans and Cryptococcus neoformans.

PubMed

Fleming, W H; Knezek, K L; Dorn, G L

1987-01-01

SOC, a fungal growth medium composed of Solryth, oxgall, and caffeic acid, was evaluated as a medium to provide rapid, differential identification of Candida albicans and Cryptococcus neoformans. Using a variety of common isolation media to produce the yeast inocula, the germ tube methods tested ranked in the following order of decreasing sensitivity: SOC (97% +/- 1), serum (92% +/- 5), rabbit coagulase plasma with EDTA in combination with tryptic soy broth (89% +/- 5), TOC (89% +/- 6), and rabbit coagulase plasma with EDTA (83% +/- 4). In chlamydospore production, SOC also proved to be the most sensitive after 24 h incubation: SOC (96% +/- 2), TOC (80% +/- 2), and cornmeal-Tween 80 agar (14% +/- 3). Other medically important yeasts showed normal patterns of growth within 24 h on SOC, thus assisting in their identification. Eighty strains of Cryptococcus neoformans showed characteristic brown pigmentation on SOC and TOC within 18 h, while all other species of the genus Cryptococcus and 229 Candida isolates did not show a change in pigmentation.

Immunity to Cryptococcus neoformans and C. gattii during cryptococcosis

PubMed Central

Gibson, Josie F.; Johnston, Simon A.

2015-01-01

The vast majority of infection with cryptococcal species occurs with Cryptococcus neoformans in the severely immunocompromised. A significant exception to this is the infections of those with apparently normal immune systems by Cryptococcus gattii. Susceptibility to cryptococcosis can be broadly categorised as a defect in adaptive immune responses, especially in T cell immunity. However, innate immune cells such as macrophages play a key role and are likely the primary effector cell in the killing and ultimate clearance of cryptococcal infection. In this review we discuss the current state of our understanding of how the immune system responds to cryptococcal infection in health and disease, with reference to the work communicated at the 9th International Conference on Cryptococcus and Cryptococcosis (ICCC9). We have focussed on cell mediated responses, particularly early in infection, but with the aim of presenting a broad overview of our understanding of immunity to cryptococcal infection, highlighting some recent advances and offering some perspectives on future directions. PMID:25498576

Unisexual versus bisexual mating in Cryptococcus neoformans: Consequences and biological impacts

PubMed Central

Fu, Ci; Sun, Sheng; Billmyre, R. Blake; Roach, Kevin C.; Heitman, Joseph

2014-01-01

Cryptococcus neoformans is an opportunistic human fungal pathogen and can undergo both bisexual and unisexual mating. Despite the fact that one mating type is dispensable for unisexual mating, the two sexual cycles share surprisingly similar features. Both mating cycles are affected by similar environmental factors and regulated by the same pheromone response pathway. Recombination takes place during unisexual reproduction in a fashion similar to bisexual reproduction and can both admix pre-existing genetic diversity and also generate diversity de novo just like bisexual reproduction. These common features may allow the unisexual life cycle to provide phenotypic and genotypic plasticity for the natural Cryptococcus population, which is predominantly α mating type, and to avoid Muller’s ratchet. The morphological transition from yeast to hyphal growth during both bisexual and unisexual mating may provide increased opportunities for outcrossing and the ability to forage for nutrients at a distance. The unisexual life cycle is a key evolutionary factor for Cryptococcus as a highly successful global fungal pathogen. PMID:25173822

[Clinical problems in medical mycology: Problem number 51].

PubMed

Romero, Mercedes; Messina, Fernando; Marín, Emmanuel; Arechavala, Alicia; Negroni, Ricardo; Depardo, Roxana; Walker, Laura; Benchetrit, Andrés; Santiso, Gabriela

A 48 year-old immunocompetent woman, who had a nodular lesion in the neck and a dense infiltrate at the lower lobe of the left lung, presented at the Mycology Unit of Muñiz Hospital of Buenos Aires City. The pulmonary infiltrate disappeared spontaneously 3 months later. The histopathological study of the nodular lesion showed capsulated yeasts (mucicarmin and alcian blue positive stains) compatible with Cryptococcus. The mycological study of a new sample, obtained by a nodular puncture, allowed the isolation of yeasts, identified as Cryptococcus gattii (VGII). Latex test for Cryptococcus capsular antigen in serum was positive (1/100). CSF cultures rendered negative results. Fluconazole at a daily dose of 800mg was given during 45 days with partial improvement; as cultures from a new clinical sample were positive for Cryptococcus, the antimycotic was changed to itraconazole 400mg/day for 5 months, with an excellent clinical response. Copyright © 2017 Asociación Española de Micología. Publicado por Elsevier España, S.L.U. All rights reserved.

A Population-Based Acute Meningitis and Encephalitis Syndromes Surveillance in Guangxi, China, May 2007- June 2012

PubMed Central

Chongsuvivatwong, Virasakdi; Wu, Xinghua; Bi, Fuyin; Hadler, Stephen C.; Jiraphongsa, Chuleeporn; Sornsrivichai, Vorasith; Lin, Mei; Quan, Yi

2015-01-01

Objectives Acute meningitis and encephalitis (AME) are common diseases with the main pathogens being viruses and bacteria. As specific treatments are different, it is important to develop clinical prediction rules to distinguish aseptic from bacterial or fungal infection. In this study we evaluated the incidence rates, seasonal variety and the main etiologic agents of AME, and identified factors that could be used to predict the etiologic agents. Methods A population-based AME syndrome surveillance system was set up in Guigang City, Guangxi, involving 12 hospitals serving the study communities. All patients meeting the case definition were investigated. Blood and/or cerebrospinal fluid were tested for bacterial pathogens using culture or RT-PCR and serological tests for viruses using enzyme-linked immunosorbent assays. Laboratory testing variables were grouped using factor analysis. Multinomial logistic regression was used to predict the etiology of AME. Results From May 2007 to June 2012, the annual incidence rate of AME syndrome, and disease specifically caused by Japanese encephalitis (JE), other viruses, bacteria and fungi were 12.55, 0.58, 4.57, 0.45 and 0.14 per 100,000 population, respectively. The top three identified viral etiologic agents were enterovirus, mumps virus, and JE virus, and for bacteria/fungi were Streptococcus sp., Cryptococcus neoformans and Staphylococcus sp. The incidence of JE and other viruses affected younger populations and peaked from April to August. Alteration of consciousness and leukocytosis were more likely to be caused by JE, bacteria and fungi whereas CSF inflammation was associated with bacterial/fungal infection. Conclusions With limited predictive validity of symptoms and signs and routine laboratory tests, specific tests for JE virus, mumps virus and enteroviruses are required to evaluate the immunization impact and plan for further intervention. CSF bacterial culture cannot be omitted in guiding clinical decisions regarding patient treatment. PMID:26633824

Phylogenetic Analysis of Phenotypically Characterized Cryptococcus laurentii Isolates Reveals High Frequency of Cryptic Species

PubMed Central

Ferreira-Paim, Kennio; Ferreira, Thatiana Bragine; Andrade-Silva, Leonardo; Mora, Delio Jose; Springer, Deborah J.; Heitman, Joseph; Fonseca, Fernanda Machado; Matos, Dulcilena; Melhem, Márcia Souza Carvalho; Silva-Vergara, Mario León

2014-01-01

Background Although Cryptococcus laurentii has been considered saprophytic and its taxonomy is still being described, several cases of human infections have already reported. This study aimed to evaluate molecular aspects of C. laurentii isolates from Brazil, Botswana, Canada, and the United States. Methods In this study, 100 phenotypically identified C. laurentii isolates were evaluated by sequencing the 18S nuclear ribosomal small subunit rRNA gene (18S-SSU), D1/D2 region of 28S nuclear ribosomal large subunit rRNA gene (28S-LSU), and the internal transcribed spacer (ITS) of the ribosomal region. Results BLAST searches using 550-bp, 650-bp, and 550-bp sequenced amplicons obtained from the 18S-SSU, 28S-LSU, and the ITS region led to the identification of 75 C. laurentii strains that shared 99–100% identity with C. laurentii CBS 139. A total of nine isolates shared 99% identity with both Bullera sp. VY-68 and C. laurentii RY1. One isolate shared 99% identity with Cryptococcus rajasthanensis CBS 10406, and eight isolates shared 100% identity with Cryptococcus sp. APSS 862 according to the 28S-LSU and ITS regions and designated as Cryptococcus aspenensis sp. nov. (CBS 13867). While 16 isolates shared 99% identity with Cryptococcus flavescens CBS 942 according to the 18S-SSU sequence, only six were confirmed using the 28S-LSU and ITS region sequences. The remaining 10 shared 99% identity with Cryptococcus terrestris CBS 10810, which was recently described in Brazil. Through concatenated sequence analyses, seven sequence types in C. laurentii, three in C. flavescens, one in C. terrestris, and one in the C. aspenensis sp. nov. were identified. Conclusions Sequencing permitted the characterization of 75% of the environmental C. laurentii isolates from different geographical areas and the identification of seven haplotypes of this species. Among sequenced regions, the increased variability of the ITS region in comparison to the 18S-SSU and 28S-LSU regions reinforces its applicability as a DNA barcode. PMID:25251413

Biofilm Formation by Cryptococcus neoformans.

PubMed

Martinez, Luis R; Casadevall, Arturo

2015-06-01

The fungus Cryptococcus neoformans possesses a polysaccharide capsule and can form biofilms on medical devices. The increasing use of ventriculoperitoneal shunts to manage intracranial hypertension associated with cryptococcal meningoencephalitis highlights the importance of investigating the biofilm-forming properties of this organism. Like other microbe-forming biofilms, C. neoformans biofilms are resistant to antimicrobial agents and host defense mechanisms, causing significant morbidity and mortality. This chapter discusses the recent advances in the understanding of cryptococcal biofilms, including the role of its polysaccharide capsule in adherence, gene expression, and quorum sensing in biofilm formation. We describe novel strategies for the prevention or eradication of cryptococcal colonization of medical prosthetic devices. Finally, we provide fresh thoughts on the diverse but interesting directions of research in this field that may result in new insights into C. neoformans biology.

Rapid method to extract DNA from Cryptococcus neoformans.

PubMed Central

Varma, A; Kwon-Chung, K J

1991-01-01

A rapid and easy method for the extraction of total cellular DNA from Cryptococcus neoformans is described. This procedure modifies and considerably simplifies previously reported methods. Numerous steps were either eliminated or replaced, including preincubations with cell wall permeability agents such as beta-mercaptoethanol and dithiothreitol. The commercially available enzyme preparation Novozyme 234 was found to contain a potent concentration of DNases which actively degrade DNA. Degradation and loss of DNA was prevented by maintaining a high concentration of EDTA in the lysing solution. This procedure resulted in high yields (150 to 200 micrograms of DNA from 100 ml of culture) of good-quality (undegraded), high-molecular-weight DNA which was readily digested by restriction endonucleases, making it suitable for use in various molecular applications. Images PMID:1909713

21 CFR 866.3165 - Cryptococcus neoformans serological reagents.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Cryptococcus neoformans serological reagents. 866.3165 Section 866.3165 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Serological Reagents § 866.3165...

21 CFR 866.3165 - Cryptococcus neoformans serological reagents.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Cryptococcus neoformans serological reagents. 866.3165 Section 866.3165 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Serological Reagents § 866.3165...

21 CFR 866.3165 - Cryptococcus neoformans serological reagents.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Cryptococcus neoformans serological reagents. 866.3165 Section 866.3165 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Serological Reagents § 866.3165...

21 CFR 866.3165 - Cryptococcus neoformans serological reagents.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Cryptococcus neoformans serological reagents. 866.3165 Section 866.3165 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Serological Reagents § 866.3165...

21 CFR 866.3165 - Cryptococcus neoformans serological reagents.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Cryptococcus neoformans serological reagents. 866.3165 Section 866.3165 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Serological Reagents § 866.3165...

Cryptococcus neoformans of Unusual Morphology

PubMed Central

Cruickshank, J. G.; Cavill, R.; Jelbert, M.

1973-01-01

A case of primary cryptococcosis of the lungs was caused by an isolate of Cryptococcus neoformans that assumes a giant form in tissue but which has a normal appearance on artificial culture. Electron microscopy revealed gross enlargement of the capsule and plasma membranes in the tissue form. Images PMID:4121033

Interleukin-15 Increases Vaccine Efficacy through a Mechanism Linked to Dendritic Cell Maturation and Enhanced Antibody Titers

DTIC Science & Technology

2007-11-26

infection with Salmo- nella enterica, Toxoplasma gondii, Plasmodium falciparum, or Cryptococcus neoformans improves host defense against, and...Spurrell, and C. J. Wood. 1998. Interleukin-15 induces antimicrobial activity after release by Cryptococcus neoformans-stimulated monocytes. J. Infect

Glucosylceramide Administration as a Vaccination Strategy in Mouse Models of Cryptococcosis.

PubMed

Mor, Visesato; Farnoud, Amir M; Singh, Ashutosh; Rella, Antonella; Tanno, Hiromasa; Ishii, Keiko; Kawakami, Kazuyoshi; Sato, Toshiya; Del Poeta, Maurizio

2016-01-01

Cryptococcus neoformans is an opportunistic fungal pathogen and the causative agent of the disease cryptococcosis. Cryptococcosis is initiated as a pulmonary infection and in conditions of immune deficiency disseminates to the blood stream and central nervous system, resulting in life-threatening meningoencephalitis. A number of studies have focused on the development of a vaccine against Cryptococcus, primarily utilizing protein-conjugated components of the Cryptococcus polysaccharide capsule as antigen. However, there is currently no vaccine against Cryptococcus in the clinic. Previous studies have shown that the glycosphingolipid, glucosylceramide (GlcCer), is a virulence factor in C. neoformans and antibodies against this lipid inhibit fungal growth and cell division. In the present study, we have investigated the possibility of using GlcCer as a therapeutic agent against C. neoformans infections in mouse models of cryptococcosis. GlcCer purified from a non-pathogenic fungus, Candida utilis, was administered intraperitoneally, prior to infecting mice with a lethal dose of C. neoformans. GlcCer administration prevented the dissemination of C. neoformans from the lungs to the brain and led to 60% mouse survival. GlcCer administration did not cause hepatic injury and elicited an anti-GlcCer antibody response, which was observed independent of the route of administration and the strains of mouse. Taken together, our results suggest that fungal GlcCer can protect mice against lethal doses of C. neoformans infection and can provide a viable vaccination strategy against Cryptococcus.

Development of an Aerosol Model of Cryptococcus Reveals Humidity as an Important Factor Affecting the Viability of Cryptococcus during Aerosolization

PubMed Central

Springer, Deborah J.; Saini, Divey; Byrnes, Edmond J.; Heitman, Joseph; Frothingham, Richard

2013-01-01

Cryptococcus is an emerging global health threat that is annually responsible for over 1,000,000 infections and one third of all AIDS patient deaths. There is an ongoing outbreak of cryptococcosis in the western United States and Canada. Cryptococcosis is a disease resulting from the inhalation of the infectious propagules from the environment. The current and most frequently used animal infection models initiate infection via liquid suspension through intranasal instillation or intravenous injection. These models do not replicate the typically dry nature of aerosol exposure and may hinder our ability to decipher the initial events that lead to clearance or the establishment of infection. We have established a standardized aerosol model of murine infection for the human fungal pathogen Cryptococcus. Aerosolized cells were generated utilizing a Collison nebulizer in a whole-body Madison Chamber at different humidity conditions. The aerosols inside the chamber were sampled using a BioSampler to determine viable aerosol concentration and spray factor (ratio of viable aerosol concentration to total inoculum concentration). We have effectively delivered yeast and yeast-spore mixtures to the lungs of mice and observed the establishment of disease. We observed that growth conditions prior to exposure and humidity within the Madison Chamber during exposure can alter Cryptococcus survival and dose retained in mice. PMID:23894542

[Preservation of high risk fungal cultures of Histoplasma and Cryptococcus].

PubMed

Fernández Andreu, C Carlos Manuel; Díaz Suárez, Luis Alberto; Ilnait Zaragozi, María Teresa; Aragonés López, Carlos; Martínez Machín, Gerardo; Perurena Lancha, Mayda R

2012-01-01

culture collections are responsible for providing the microbial resources for development of biological sciences. Storage in distilled water is one of the easiest and least expensive method for long-term fungal preservation. to evaluate the usefulness of this preservation method in fungal culture of Histoplasma and Cryptococcus. the preservation condition of the highest biological risk species from Histoplasma y Cryptococcus genera, included in the fungal culture collection of "Pedro Kouri" Institute of Tropical Medicine in Havana, was evaluated in this study. One hundred and two strains stored in distilled water, 92% of which had been preserved for more than 10 years, were analyzed. the percentages of recovered strains from H. capsulatum, C. neoformans and C. gattii were 64.3%; 79.1% and 100% respectively. This method of preservation proved to be satisfactory for fungal culture in labs with limited financial resources. A web-based database with interesting information about the collection was made. The importance of strict compliance with the biosafety measures in these collections, particularly with high risk pathogens. preservation of fungal cultures in distilled water is a very useful method for laboratories with limited resources. Culture collections should be assumed as an essential activity in order to solve increasing challenges in the development of biomedical sciences.

Antarctic Yeasts: Biodiversity and Potential Applications

NASA Astrophysics Data System (ADS)

Shivaji, S.; Prasad, G. S.

This review is an attempt in cataloguing the diversity of yeasts in Antarctica, highlight their biotechnological potential and understand the basis of adaptation to low temperature. As of now several psychrophilic and psychrotolerant yeasts from Antarctic soils and marine waters have been characterized with respect to their growth characteristics, ecological distribution and taxonomic significance. Interestingly most of these species belonged to basidiomycetous yeasts which as a group are known for their ability to circumvent and survive under stress conditions. Simultaneously their possible role as work horses in the biotechnological industry was recognized due to their ability to produce novel enzymes and biomolecules such as agents for the breakdown of xenobiotics, and novel pharmaceutical chemi cals. The high activity of psychrophilic enzymes at low and moderate temperatures offers potential economic benefits. As of now lipases from Pseudozyma antarctica have been extensively studied to understand their unique thermal stability at 90°C and also because of its use in the pharmaceutical, agriculture, food, cosmetics and chemical industry. A few of the other enzymes which have been studied include extracellular alpha-amylase and glucoamylase from the yeast Pseudozyma antarctica (Candida antarctica), an extra-cellular protease from Cryptococcus humicola, an aspartyl proteinase from Cryptococcus humicola, a novel extracellular subtilase from Leucosporidium antarcticum, and a xylanase from Cryptococcus adeliensis

Specificity of Cryptococcus fagisuga and Nectria coccinea association in beech bark disease in Europe

Treesearch

R. Perrin

1983-01-01

The specificity of the Cryptococcus fagisuga and N. coccinea association is studied by artificial inoculation of 4 species of Nectria: N. coccinea, N. ditissima. N. galligena and N. cinnabarina on bark infested with beech scale. N. coccinea appears to be the most efficient...

Genotypic and phenotypic characterization of Cryptococcus flavescens, beneficial biocontrol agents for controlling Fusarium head blight of wheat

USDA-ARS?s Scientific Manuscript database

Cryptococcus flavescens strain OH182.9_3C (3C) previously displayed significant biological control activity against Fusarium head blight, a globally important disease of wheat; however, the diversity within C. flavescens has not been previously characterized. Multilocus sequence typing was performed...

Draft genome sequence of Cryptococcus terricola JCM 24523, an oleaginous yeast capable of expressing exogenous DNA

DOE PAGES

Close, Dan; Ojumu, John O.; Zhang, Gui X.

2016-11-03

Cryptococcus terricola JCM 24523 has recently been identified as an oleaginous yeast capable of converting starch into fatty acids. Here, this draft genome sequence provides a platform for elucidating its fatty acid production potential and supporting comparisons with other oleaginous species.

Draft genome sequence of Cryptococcus terricola JCM 24523, an oleaginous yeast capable of expressing exogenous DNA

DOE Office of Scientific and Technical Information (OSTI.GOV)

Close, Dan; Ojumu, John O.; Zhang, Gui X.

Cryptococcus terricola JCM 24523 has recently been identified as an oleaginous yeast capable of converting starch into fatty acids. Here, this draft genome sequence provides a platform for elucidating its fatty acid production potential and supporting comparisons with other oleaginous species.

Determining Antifungal Target Sites in the Sterol Pathway of the Yeast Candida and Saccharomyces

DTIC Science & Technology

1997-10-01

interaction of the azole antifungal agent SCH39304 with the cytochrome P-450 monooxygenase system isolated from Cryptococcus neoformans. Antimicrob. Agents...isolates of Cryptococcus neoformans. Antimicrob. Agents Chemother. 41: 748-751. 16. Wheat, J., Marichal, P., Vanden Bossche, H., Le Monte, A., and

Fusarium and other opportunistic hyaline fungi

USDA-ARS?s Scientific Manuscript database

This chapter focuses on those fungi that grow in tissue in the form of hyaline or lightly colored septate hyphae. These fungi include Fusarium and other hyaline fungi. Disease caused by hyaline fungi is referred to as hyalohyphomycosis. Hyaline fungi described in this chapter include the anamorphic,...

Two cation transporters Ena1 and Nha1 cooperatively modulate ion homeostasis, antifungal drug resistance, and virulence of Cryptococcus neoformans via the HOG pathway

PubMed Central

Jung, Kwang-Woo; Strain, Anna K; Nielsen, Kirsten; Jung, Kwang-Hwan; Bahn, Yong-Sun

2012-01-01

Maintenance of cation homeostasis is essential for survival of all living organisms in their biological niches. It is also important for the survival of human pathogenic fungi in the host, where cation concentrations and pH will vary depending on different anatomical sites. However, the exact role of diverse cation transporters and ion channels in virulence of fungal pathogens remains elusive. In this study we functionally characterized ENA1 and NHA1, encoding a putative Na+/ATPase and Na+/H+ antiporter, respectively, in Cryptococcus neoformans, a basidiomycete fungal pathogen which causes fatal meningoencephalitis. Expression of NHA1 and ENA1 is induced in response to salt and osmotic shock mainly in a Hog1-dependent manner. Phenotypic analysis of the ena1, nha1, and ena1 nha1 mutants revealed that Ena1 controls cellular levels of toxic cations, such as Na+ and Li+ whereas both Ena1 and Nha1 are important for controlling less toxic K+ ions. Under alkaline conditions, Ena1 was highly induced and required for growth in the presence of low levels of Na+ or K+ salt and Nha1 played a role in survival under K+ stress. In contrast, Nha1, but not Ena1, was essential for survival at acidic conditions (pH 4.5) under high K+ stress. In addition, Ena1 and Nha1 were required for maintenance of plasma membrane potential and stability, which appeared to modulate antifungal drug susceptibility. Perturbation of ENA1 and NHA1 enhanced capsule production and melanin synthesis. However, Nha1 was dispensable for virulence of C. neoformans although Ena1 was essential. In conclusion, Ena1 and Nha1 play redundant and discrete roles in cation homeostasis, pH regulation, membrane potential, and virulence in C. neoformans, suggesting that these transporters could be novel antifungal drug targets for treatment of cryptococcosis. PMID:22343280

Trojan Horse Transit Contributes to Blood-Brain Barrier Crossing of a Eukaryotic Pathogen.

PubMed

Santiago-Tirado, Felipe H; Onken, Michael D; Cooper, John A; Klein, Robyn S; Doering, Tamara L

2017-01-31

The blood-brain barrier (BBB) protects the central nervous system (CNS) by restricting the passage of molecules and microorganisms. Despite this barrier, however, the fungal pathogen Cryptococcus neoformans invades the brain, causing a meningoencephalitis that is estimated to kill over 600,000 people annually. Cryptococcal infection begins in the lung, and experimental evidence suggests that host phagocytes play a role in subsequent dissemination, although this role remains ill defined. Additionally, the disparate experimental approaches that have been used to probe various potential routes of BBB transit make it impossible to assess their relative contributions, confounding any integrated understanding of cryptococcal brain entry. Here we used an in vitro model BBB to show that a "Trojan horse" mechanism contributes significantly to fungal barrier crossing and that host factors regulate this process independently of free fungal transit. We also, for the first time, directly imaged C. neoformans-containing phagocytes crossing the BBB, showing that they do so via transendothelial pores. Finally, we found that Trojan horse crossing enables CNS entry of fungal mutants that cannot otherwise traverse the BBB, and we demonstrate additional intercellular interactions that may contribute to brain entry. Our work elucidates the mechanism of cryptococcal brain invasion and offers approaches to study other neuropathogens. The fungal pathogen Cryptococcus neoformans invades the brain, causing a meningoencephalitis that kills hundreds of thousands of people each year. One route that has been proposed for this brain entry is a Trojan horse mechanism, whereby the fungus crosses the blood-brain barrier (BBB) as a passenger inside host phagocytes. Although indirect experimental evidence supports this intriguing mechanism, it has never been directly visualized. Here we directly image Trojan horse transit and show that it is regulated independently of free fungal entry, contributes to cryptococcal BBB crossing, and allows mutant fungi that cannot enter alone to invade the brain. Copyright © 2017 Santiago-Tirado et al.

Tracking native and applied populations of Cryptococcus flavescens in the environment

USDA-ARS?s Scientific Manuscript database

Cryptococcus flavescens strain OH182.9_3C (3C) exhibits biological control efficacy against Fusarium Head Blight, a globally important disease of wheat. In this study, a quantitative PCR (qPCR) assay of SYBR® Green chemistry targeting a Heat Shock Protein 70 kDa gene was developed and applied to mon...

Wood and bark anatomy of young beech in relation to Cryptococcus attack

Treesearch

David Lonsdale

1983-01-01

Within a sample of European beech, partial resistance to attack by the beech scale, Cryptococcus fagisuga, was associated with a smooth bark which had a regular, vertical pattern in its surface 'growth lines'. Such bark contained relatively little lignified outer parenchyma, and the main stone cell layer was strongly developed. The '...

Draft genome sequence of the oleaginous yeast Cryptococcus curvatus ATCC 20509

DOE Office of Scientific and Technical Information (OSTI.GOV)

Close, Dan; Ojumu, John O.

Cryptococcus curvatus ATCC 20509 is a commonly used nonmodel oleaginous yeast capable of converting a variety of carbon sources into fatty acids. In addition, we present the draft genome sequence of this popular organism to provide a means for more in-depth studies of its fatty acid production potential.

Melanin Biosynthesis in Cryptococcus neoformans

PubMed Central

Williamson, Peter R.; Wakamatsu, Kazumasa; Ito, Shosuke

1998-01-01

Pigment production by Cryptococcus neoformans is virulence associated. Dopamine- and 3,4-dihydroxyphenylalanine–melanin products were identified after acidic permanganate oxidation, alkaline hydrogen peroxide oxidation, or hydrolysis with hydriodic acid. These data provide direct chemical evidence for the formation of eumelanin polymers by catecholamine oxidation by laccase alone followed by oxidative coupling of dihydroxyindole. PMID:9515929

A rapid and easy method for the DNA extraction from Cryptococcus neoformans

PubMed Central

2011-01-01

DNA isolation from C. neoformans is difficult due to a thick and resistant capsule. We have optimized a new and rapid DNA isolation method for Cryptococcus using a short urea treatment followed by a rapid method using a chelex resin suspension. This procedure is simpler than previously reported methods. PMID:21777412

U.S. Army Medical Bioengineering Research and Development Laboratory Annual Progress Report FY 1985. Volume 1

DTIC Science & Technology

1985-10-01

heterotrophic carbon dioxide fixa- tion. An assay for T2 toxin using the yeast Cryptococcus luteolus was evaluated as a rapid screening device for toxic...Bioassay for Mycotoxins Using Cryptococcus luteolus with Tetrazolium Salts." Poster session at the American Soc. for Microbiol. Annual Meeting, March

Draft genome sequence of the oleaginous yeast Cryptococcus curvatus ATCC 20509

DOE PAGES

Close, Dan; Ojumu, John O.

2016-11-03

Cryptococcus curvatus ATCC 20509 is a commonly used nonmodel oleaginous yeast capable of converting a variety of carbon sources into fatty acids. In addition, we present the draft genome sequence of this popular organism to provide a means for more in-depth studies of its fatty acid production potential.

Cryptococcus neoformans granuloma in the lung and spinal cord of a free-ranging cheetah (Acinonyx jubatus). A clinical report and literature review.

PubMed

Millward, I R; Williams, M C

2005-12-01

A 6-year-old, male, wild-born, free-ranging cheetah (Acinonyx jubatus) was evaluated for acute onset of progressive lameness in the right hind limb. Survey radiographs were unrewarding and myelography indicated an intramedullary compressive mass at the L3-L4 region. A fine needle aspirate of the lesion indicated the presence of Cryptococcus organisms. Necropsy confirmed the presence of granulomas (cryptococcoma) in the lung and the spinal cord (meningomyelitis) caused by Cryptococcus neoformans var. gattii. Cryptococcus neoformans is a yeast-like organism that is a potential pathogen to many species. Initial infection is thought to be of respiratory origin and then it commonly disseminates systemically from the nasal cavity or lungs to the skin, eyes and central nervous system in particular. The cheetah tested negative for both feline leukaemia virus (FeLV) and feline immunodeficiency virus (FIV), as have all the previously reported cheetah cases. C. neoformans is a non-contagious, opportunistic organism and is the most common systemic mycoses in domestic cats and the cheetah.

Cryptococcus nanyangensis sp. nov., a new basidiomycetous yeast isolated from the gut of wood-boring larvae.

PubMed

Hui, Feng-Li; Niu, Qiu-Hong; Ke, Tao; Li, Ying-Xia

2012-11-01

Two strains of a novel basidiomycetous yeast species were isolated from the gut of wood-boring larvae collected in the Baotianman Nature Reserve, the central China. Sequence analysis of the D1/D2 domains of the large subunit (LSU) rRNA gene and internal transcribed spacer (ITS) regions showed that these yeasts belong to the Bulleromyces clade and formed a cluster together with eleven undescribed Cryptococcus species. The novel species differed from its closest known species, Cryptococcus rajasthanensis, by 3.3 % divergence (15 substitutions and 6 gaps over 630 bases) in the D1/D2 domains, and by 13.4 % divergence (41 substitutions and 27 gaps over 508 bases) in the ITS regions. Physiologically, the fermentation of glucose, galactose, sucrose, trehalose, and raffinose in Durham tubes was observed for the strains of this new yeast. Based on the phenotypical and molecular characteristics presented, the two strains are proposed as a new species, Cryptococcus nanyangensis sp. nov., with the type strain KCY-1(T) (=CICC 1976(T) = CBS 12474(T)).

Validation and clinical application of a molecular method for the identification of Cryptococcus neoformans/Cryptococcus gattii complex DNA in human clinical specimens.

PubMed

Rivera, Vanessa; Gaviria, Marcela; Muñoz-Cadavid, Cesar; Cano, Luz; Naranjo, Tonny

2015-01-01

The diagnosis of cryptococcosis is usually performed based on cultures of tissue or body fluids and isolation of the fungus, but this method may require several days. Direct microscopic examination, although rapid, is relatively insensitive. Biochemical and immunodiagnostic rapid tests are also used. However, all of these methods have limitations that may hinder final diagnosis. The increasing incidence of fungal infections has focused attention on tools for rapid and accurate diagnosis using molecular biological techniques. Currently, PCR-based methods, particularly nested, multiplex and real-time PCR, provide both high sensitivity and specificity. In the present study, we evaluated a nested PCR targeting the gene encoding the ITS-1 and ITS-2 regions of rDNA in samples from a cohort of patients diagnosed with cryptococcosis. The results showed that in our hands, this Cryptococcus nested PCR assay has 100% specificity and 100% sensitivity and was able to detect until 2 femtograms of Cryptococcus DNA. Copyright © 2015 Elsevier Editora Ltda. All rights reserved.

It's not all about us: evolution and maintenance of Cryptococcus virulence requires selection outside the human host.

PubMed

Gerstein, Aleeza C; Nielsen, Kirsten

2017-04-01

Cryptococcus is predominantly an AIDS-related pathogen that causes significant morbidity and mortality in immunocompromised patients. Research studies have historically focused on understanding how the organism causes human disease through the use of in vivo and in vitro model systems to identify virulence factors. Cryptococcus is not an obligate pathogen, however, as human-human transmission is either absent or rare. Selection in the environment must thus be invoked to shape the evolution of this taxa, and directly influences genotypic and trait diversity. Importantly, the evolution and maintenance of pathogenicity must also stem directly from environmental selection. To that end, here we examine abiotic and biotic stresses in the environment, and discuss how they could shape the factors that are commonly identified as important virulence traits. We identify a number of important unanswered questions about Cryptococcus diversity and evolution that are critical for understanding this deadly pathogen, and discuss how implementation of modern sampling and genomic tools could be utilized to answer these questions. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

Isolation of a new broad spectrum antifungal polyene from Streptomyces sp. MTCC 5680.

PubMed

Vartak, A; Mutalik, V; Parab, R R; Shanbhag, P; Bhave, S; Mishra, P D; Mahajan, G B

2014-06-01

A new polyene macrolide antibiotic PN00053 was isolated from the fermentation broth of Streptomyces sp. wild-type strain MTCC-5680. The producer strain was isolated from fertile mountain soil of Naldehra region, Himachal Pradesh, India. The compound PN00053 was purified through various steps of chromatographic techniques and bio-activity guided fractionation followed by its characterization using physiochemical properties, spectral data ((1) H-NMR, (13) C-NMR, HMBC, HSQC, and COSY) and MS analysis. PN00053 exhibited broad spectrum in vitro antifungal activity against strains of Aspergillus fumigatus (HMR), A. fumigatus ATCC 16424, Candida albicans (I.V.), C. albicans ATCC 14503, C. krusei GO6, C. glabrata HO4, Cryptococcus neoformans, Trichophyton sp. as well as fluconazole resistant strains C. krusei GO3 and C. glabrata HO5. It did not inhibit growth of gram positive and gram-negative bacteria, displaying its specificity against fungi. PN00053 is a novel polyene macrolide isolated from a wild strain of Streptomyces sp. PM0727240 (MTCC5680), an isolate from the mountainous rocky regions of Himachal Pradesh, India. The compound is a new derivative of the antibiotic Roflamycoin [32, 33-didehydroroflamycoin (DDHR)]. It displayed broad spectrum antifungal activity against yeast and filamentous fungi. However, it did not show any antibacterial activity. The in vitro study revealed that PN00053 has better potency as compared to clinical gold standard fluconazole. The development of pathogenic resistance against the polyenes has been seldom reported. Hence, we envisage PN00053 could be a potential antifungal lead. © 2014 The Society for Applied Microbiology.

Ionizing radiation changes the electronic properties of melanin and enhances the growth of melanized fungi.

PubMed

Dadachova, Ekaterina; Bryan, Ruth A; Huang, Xianchun; Moadel, Tiffany; Schweitzer, Andrew D; Aisen, Philip; Nosanchuk, Joshua D; Casadevall, Arturo

2007-05-23

Melanin pigments are ubiquitous in nature. Melanized microorganisms are often the dominating species in certain extreme environments, such as soils contaminated with radionuclides, suggesting that the presence of melanin is beneficial in their life cycle. We hypothesized that ionizing radiation could change the electronic properties of melanin and might enhance the growth of melanized microorganisms. Ionizing irradiation changed the electron spin resonance (ESR) signal of melanin, consistent with changes in electronic structure. Irradiated melanin manifested a 4-fold increase in its capacity to reduce NADH relative to non-irradiated melanin. HPLC analysis of melanin from fungi grown on different substrates revealed chemical complexity, dependence of melanin composition on the growth substrate and possible influence of melanin composition on its interaction with ionizing radiation. XTT/MTT assays showed increased metabolic activity of melanized C. neoformans cells relative to non-melanized cells, and exposure to ionizing radiation enhanced the electron-transfer properties of melanin in melanized cells. Melanized Wangiella dermatitidis and Cryptococcus neoformans cells exposed to ionizing radiation approximately 500 times higher than background grew significantly faster as indicated by higher CFUs, more dry weight biomass and 3-fold greater incorporation of (14)C-acetate than non-irradiated melanized cells or irradiated albino mutants. In addition, radiation enhanced the growth of melanized Cladosporium sphaerospermum cells under limited nutrients conditions. Exposure of melanin to ionizing radiation, and possibly other forms of electromagnetic radiation, changes its electronic properties. Melanized fungal cells manifested increased growth relative to non-melanized cells after exposure to ionizing radiation, raising intriguing questions about a potential role for melanin in energy capture and utilization.

Immune Recognition of Fungal Polysaccharides.

PubMed

Snarr, Brendan D; Qureshi, Salman T; Sheppard, Donald C

2017-08-28

The incidence of fungal infections has dramatically increased in recent years, in large part due to increased use of immunosuppressive medications, as well as aggressive medical and surgical interventions that compromise natural skin and mucosal barriers. There are relatively few currently licensed antifungal drugs, and rising resistance to these agents has led to interest in the development of novel preventative and therapeutic strategies targeting these devastating infections. One approach to combat fungal infections is to augment the host immune response towards these organisms. The polysaccharide-rich cell wall is the initial point of contact between fungi and the host immune system, and therefore, represents an important target for immunotherapeutic approaches. This review highlights the advances made in our understanding of the mechanisms by which the immune system recognizes and interacts with exopolysaccharides produced by four of the most common fungal pathogens: Aspergillus fumigatus , Candida albicans , Cryptococcus neoformans , and Histoplasma capsulatum . Work to date suggests that inner cell wall polysaccharides that play an important structural role are the most conserved across diverse members of the fungal kingdom, and elicit the strongest innate immune responses. The immune system senses these carbohydrates through receptors, such as lectins and complement proteins. In contrast, a greater diversity of polysaccharides is found within the outer cell walls of pathogenic fungi. These glycans play an important role in immune evasion, and can even induce anti-inflammatory host responses. Further study of the complex interactions between the host immune system and the fungal polysaccharides will be necessary to develop more effective therapeutic strategies, as well as to explore the use of immunosuppressive polysaccharides as therapeutic agents to modulate inflammation.

Prevalence of culturable airborne spores of selected allergenic and pathogenic fungi in outdoor air

NASA Astrophysics Data System (ADS)

O'Gorman, Céline M.; Fuller, Hubert T.

2008-06-01

Temporal and spatial variations in airborne spore concentrations of selected allergenic and pathogenic fungi were examined in Dublin, Ireland, in 2005. Air samples were taken at four outdoor locations in the city every 2 weeks, coupled with measurements of meteorological conditions. Total culturable airborne fungal spore concentrations in Dublin ranged from 30-6800 colony forming units per cubic metre of air (CFU m-3) over the 12-month period. Cladosporium, Penicillium, Aspergillus and Alternaria spores were constantly present in the Dublin atmosphere, representing >20% of the total culturable spore count. Concentrations of Cladosporium increased significantly in summer and reached allergenic threshold levels, peaking at over 3200 CFU m-3 in August. Penicillium spore concentrations never reached allergenic threshold levels, with average concentrations of <150 CFU m-3. Alternaria conidia formed only 0.3% of the total culturable fungal spore count and concentrations never exceeded 50 CFU m-3, attributable to the coastal position of Dublin and its low levels of arable production. The opportunistic human pathogen Aspergillus fumigatus was present throughout the year in nominal concentrations (<10 CFU m-3), but sporadic high counts were also recorded (300-400 CFU m-3), the potential health implications of which give cause for concern. Spores of neither Cryptococcus neoformans nor Stachybotrys chartarum were detected, but airborne basidiospores of Schizophyllum commune were evidenced by the dikaryotization of monokaryon tester strains following exposure to the air. The relationships between airborne fungal spore concentrations and meteorological factors were analysed by redundancy analysis and revealed positive correlations between temperature and Cladosporium and relative humidity and Penicillium and Aspergillus.

Determination of chitin content in fungal cell wall: an alternative flow cytometric method.

PubMed

Costa-de-Oliveira, Sofia; Silva, Ana P; Miranda, Isabel M; Salvador, Alexandre; Azevedo, Maria M; Munro, Carol A; Rodrigues, Acácio G; Pina-Vaz, Cidália

2013-03-01

The conventional methods used to evaluate chitin content in fungi, such as biochemical assessment of glucosamine release after acid hydrolysis or epifluorescence microscopy, are low throughput, laborious, time-consuming, and cannot evaluate a large number of cells. We developed a flow cytometric assay, efficient, and fast, based on Calcofluor White staining to measure chitin content in yeast cells. A staining index was defined, its value was directly related to chitin amount and taking into consideration the different levels of autofluorecence. Twenty-two Candida spp. and four Cryptococcus neoformans clinical isolates with distinct susceptibility profiles to caspofungin were evaluated. Candida albicans clinical isolate SC5314, and isogenic strains with deletions in chitin synthase 3 (chs3Δ/chs3Δ) and genes encoding predicted GlycosylPhosphatidylInositol (GPI)-anchored proteins (pga31Δ/Δ and pga62Δ/Δ), were used as controls. As expected, the wild-type strain displayed a significant higher chitin content (P < 0.001) than chs3Δ/chs3Δ and pga31Δ/Δ especially in the presence of caspofungin. Ca. parapsilosis, Ca. tropicalis, and Ca. albicans showed higher cell wall chitin content. Although no relationship between chitin content and antifungal drug susceptibility phenotype was found, an association was established between the paradoxical growth effect in the presence of high caspofungin concentrations and the chitin content. This novel flow cytometry protocol revealed to be a simple and reliable assay to estimate cell wall chitin content of fungi. Copyright © 2013 International Society for Advancement of Cytometry.

Cryptococcus gattii in North American Pacific Northwest: Whole-Population Genome Analysis Provides Insights into Species Evolution and Dispersal

PubMed Central

Engelthaler, David M.; Hicks, Nathan D.; Gillece, John D.; Roe, Chandler C.; Schupp, James M.; Driebe, Elizabeth M.; Gilgado, Felix; Carriconde, Fabian; Trilles, Luciana; Firacative, Carolina; Ngamskulrungroj, Popchai; Castañeda, Elizabeth; Lazera, Marcia dos Santos; Melhem, Marcia S. C.; Pérez-Bercoff, Åsa; Huttley, Gavin; Sorrell, Tania C.; Voelz, Kerstin; May, Robin C.; Fisher, Matthew C.; Thompson, George R.; Lockhart, Shawn R.

2014-01-01

ABSTRACT The emergence of distinct populations of Cryptococcus gattii in the temperate North American Pacific Northwest (PNW) was surprising, as this species was previously thought to be confined to tropical and semitropical regions. Beyond a new habitat niche, the dominant emergent population displayed increased virulence and caused primary pulmonary disease, as opposed to the predominantly neurologic disease seen previously elsewhere. Whole-genome sequencing was performed on 118 C. gattii isolates, including the PNW subtypes and the global diversity of molecular type VGII, to better ascertain the natural source and genomic adaptations leading to the emergence of infection in the PNW. Overall, the VGII population was highly diverse, demonstrating large numbers of mutational and recombinational events; however, the three dominant subtypes from the PNW were of low diversity and were completely clonal. Although strains of VGII were found on at least five continents, all genetic subpopulations were represented or were most closely related to strains from South America. The phylogenetic data are consistent with multiple dispersal events from South America to North America and elsewhere. Numerous gene content differences were identified between the emergent clones and other VGII lineages, including genes potentially related to habitat adaptation, virulence, and pathology. Evidence was also found for possible gene introgression from Cryptococcus neoformans var. grubii that is rarely seen in global C. gattii but that was present in all PNW populations. These findings provide greater understanding of C. gattii evolution in North America and support extensive evolution in, and dispersal from, South America. PMID:25028429

Pseudohyphal growth of Cryptococcus neoformans is a reversible dimorphic transition in response to ammonium that requires Amt1 and Amt2 ammonium permeases.

PubMed

Lee, Soo Chan; Phadke, Sujal; Sun, Sheng; Heitman, Joseph

2012-11-01

Cryptococcus neoformans is a human-pathogenic basidiomycete that commonly infects HIV/AIDS patients to cause meningoencephalitis (7, 19). C. neoformans grows as a budding yeast during vegetative growth or as hyphae during sexual reproduction. Pseudohyphal growth of C. neoformans has been observed rarely during murine and human infections but frequently during coculture with amoeba; however, the genetics underlying pseudohyphal growth are largely unknown. Our studies found that C. neoformans displays pseudohyphal growth under nitrogen-limiting conditions, especially when a small amount of ammonium is available as a sole nitrogen source. Pseudohyphal growth was observed with Cryptococcus neoformans serotypes A and D and Cryptococcus gattii. C. neoformans pseudohyphae bud to produce yeast cells and normal smooth hemispherical colonies when transferred to complete media, indicating that pseudohyphal growth is a conditional developmental stage. Subsequent analysis revealed that two ammonium permeases encoded by the AMT1 and AMT2 genes are required for pseudohyphal growth. Both amt1 and amt2 mutants are capable of forming pseudohyphae; however, amt1 amt2 double mutants do not form pseudohyphae. Interestingly, C. gattii pseudohypha formation is irreversible and involves a RAM pathway mutation that drives pseudohyphal development. We also found that pseudohyphal growth is related to the invasive growth into the medium. These results demonstrate that pseudohyphal growth is a common reversible growth pattern in C. neoformans but a mutational genetic event in C. gattii and provide new insights into understanding pseudohyphal growth of Cryptococcus.

Glucosylceramide Administration as a Vaccination Strategy in Mouse Models of Cryptococcosis

PubMed Central

Mor, Visesato; Farnoud, Amir M.; Singh, Ashutosh; Rella, Antonella; Tanno, Hiromasa; Ishii, Keiko; Kawakami, Kazuyoshi; Sato, Toshiya; Del Poeta, Maurizio

2016-01-01

Cryptococcus neoformans is an opportunistic fungal pathogen and the causative agent of the disease cryptococcosis. Cryptococcosis is initiated as a pulmonary infection and in conditions of immune deficiency disseminates to the blood stream and central nervous system, resulting in life-threatening meningoencephalitis. A number of studies have focused on the development of a vaccine against Cryptococcus, primarily utilizing protein-conjugated components of the Cryptococcus polysaccharide capsule as antigen. However, there is currently no vaccine against Cryptococcus in the clinic. Previous studies have shown that the glycosphingolipid, glucosylceramide (GlcCer), is a virulence factor in C. neoformans and antibodies against this lipid inhibit fungal growth and cell division. In the present study, we have investigated the possibility of using GlcCer as a therapeutic agent against C. neoformans infections in mouse models of cryptococcosis. GlcCer purified from a non-pathogenic fungus, Candida utilis, was administered intraperitoneally, prior to infecting mice with a lethal dose of C. neoformans. GlcCer administration prevented the dissemination of C. neoformans from the lungs to the brain and led to 60% mouse survival. GlcCer administration did not cause hepatic injury and elicited an anti-GlcCer antibody response, which was observed independent of the route of administration and the strains of mouse. Taken together, our results suggest that fungal GlcCer can protect mice against lethal doses of C. neoformans infection and can provide a viable vaccination strategy against Cryptococcus. PMID:27082428

In Vitro Antifungal Activities of a Series of Dication-Substituted Carbazoles, Furans, and Benzimidazoles

PubMed Central

Del Poeta, Maurizio; Schell, Wiley A.; Dykstra, Christine C.; Jones, Susan K.; Tidwell, Richard R.; Kumar, Arvind; Boykin, David W.; Perfect, John R.

1998-01-01

Aromatic dicationic compounds possess antimicrobial activity against a wide range of eucaryotic pathogens, and in the present study an examination of the structures-functions of a series of compounds against fungi was performed. Sixty-seven dicationic molecules were screened for their inhibitory and fungicidal activities against Candida albicans and Cryptococcus neoformans. The MICs of a large number of compounds were comparable to those of the standard antifungal drugs amphotericin B and fluconazole. Unlike fluconazole, potent inhibitory compounds in this series were found to have excellent fungicidal activities. The MIC of one of the most potent compounds against C. albicans was 0.39 μg/ml, and it was the most potent compound against C. neoformans (MIC, ≤0.09 μg/ml). Selected compounds were also found to be active against Aspergillus fumigatus, Fusarium solani, Candida species other than C. albicans, and fluconazole-resistant strains of C. albicans and C. neoformans. Since some of these compounds have been safely given to animals, these classes of molecules have the potential to be developed as antifungal agents. PMID:9756748

The effects of gamma radiation, UV and visible light on ATP levels in yeast cells depend on cellular melanization.

PubMed

Bryan, Ruth; Jiang, Zewei; Friedman, Matthew; Dadachova, Ekaterina

2011-10-01

Previously we have shown that growth of melanized fungi is stimulated by low levels of gamma radiation. The goal of this study was to examine the effects of visible light, UV light, and gamma radiation on the energy level (ATP concentration) in melanized Cryptococcus neoformans cells. Melanized C. neoformans cells as well as non-melanized controls were subjected to visible, UV or gamma radiation, and ATP was quantified by measuring the amount of light emitted by the ATP-dependent reaction of luciferase with luciferin. We found that all three forms of radiation led to a reduction in the ATP levels in melanized C. neoformans cells. This points to a universal melanin-related mechanism underlying observation of ATP decrease in irradiated melanized cells. In contrast, in non-melanized cells visible light led to increase in ATP levels; gamma radiation did not cause any changes while UV exposure resulted in some ATP decrease, however, much less pronounced than in melanized cells. Copyright © 2011 British Mycological Society. Published by Elsevier Ltd. All rights reserved.

Biologically active and thermally stable polymeric Schiff base and its metal polychelates: Their synthesis and spectral aspects

NASA Astrophysics Data System (ADS)

Rasool, Raza; Hasnain, Sumaiya

2015-09-01

New metal polychelates of Mn(II), Co(II), Ni(II), Cu(II) and Zn(II) obtained by the interaction of metal acetates with polymeric Schiff base containing formaldehyde and piperazine, have been investigated. Structural and spectroscopic properties have been evaluated by elemental analysis, FT-IR and 1H-NMR. Geometry of the chelated polymers was confirmed by magnetic susceptibility measurements, UV-Visible spectroscopy and Electron Spin Resonance. The molecular weight of the polymer was determined by gel permeation chromatography (GPC). Thermogravimetric analysis indicated that metal polychelates were more thermally stable than their corresponding ligand. All compounds were screened for their antimicrobial activities against Escherichia coli, Staphylococcus aureus, Bacillus subtilis, (bacteria) and Candida albicans, Microsporum canis, Cryptococcus neoformans (fungi) by agar well diffusion method. Interestingly, the polymeric Schiff base was found to be antimicrobial in nature but less effective as compared to the metal polychelates. On the basis of thermal and antimicrobial behavior, these polymers hold potential applications as thermally resistant antimicrobial and antifouling coating materials as well as antimicrobial packaging materials.

Call for Action: Invasive Fungal Infections Associated With Ibrutinib and Other Small Molecule Kinase Inhibitors Targeting Immune Signaling Pathways.

PubMed

Chamilos, Georgios; Lionakis, Michail S; Kontoyiannis, Dimitrios P

2018-01-06

Opportunistic infections caused by Pneumocystis jirovecii, Cryptococcus neoformans, and ubiquitous airborne filamentous fungi have been recently reported in patients with hematological cancers historically considered at low risk for invasive fungal infections (IFIs), after receipt of the Bruton tyrosine kinase inhibitor ibrutinib. The spectrum and severity of IFIs often observed in these patients implies the presence of a complex immunodeficiency that may not be solely attributed to mere inhibition of Bruton tyrosine kinase. In view of the surge in development of small molecule kinase inhibitors for treatment of malignant and autoimmune diseases, it is possible that there would be an emergence of IFIs associated with the effects of these molecules on the immune system. Preclinical assessment of the immunosuppressive effects of kinase inhibitors and human studies aimed at improving patient risk stratification for development of IFIs could lead to prevention, earlier diagnosis, and better outcomes in affected patients. © The Author(s) 2017. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail: journals.permissions@oup.com.

Diversity of soil yeasts isolated from South Victoria Land, Antarctica

USGS Publications Warehouse

Connell, L.; Redman, R.; Craig, S.; Scorzetti, G.; Iszard, M.; Rodriguez, R.

2008-01-01

Unicellular fungi, commonly referred to as yeasts, were found to be components of the culturable soil fungal population in Taylor Valley, Mt. Discovery, Wright Valley, and two mountain peaks of South Victoria Land, Antarctica. Samples were taken from sites spanning a diversity of soil habitats that were not directly associated with vertebrate activity. A large proportion of yeasts isolated in this study were basidiomycetous species (89%), of which 43% may represent undescribed species, demonstrating that culturable yeasts remain incompletely described in these polar desert soils. Cryptococcus species represented the most often isolated genus (33%) followed by Leucosporidium (22%). Principle component analysis and multiple linear regression using stepwise selection was used to model the relation between abiotic variables (principle component 1 and principle component 2 scores) and yeast biodiversity (the number of species present at a given site). These analyses identified soil pH and electrical conductivity as significant predictors of yeast biodiversity. Species-specific PCR primers were designed to rapidly discriminate among the Dioszegia and Leucosporidium species collected in this study. ?? 2008 Springer Science+Business Media, LLC.

Clinical characteristics and predictors of mortality for Cryptococcus gattii infection in dogs and cats of southwestern British Columbia

PubMed Central

Duncan, Colleen; Stephen, Craig; Campbell, John

2006-01-01

Since 1999, Cryptococcus gattii has emerged as an important pathogen of humans and animals in southwestern British Columbia. Historically thought to be restricted to the tropics and subtropics, C. gattii has posed new diagnostic and treatment challenges to veterinary practitioners working within the recently identified endemic region. Clinical reports of canine and feline cryptococcosis caused by C. gattii diagnosed between January 1999 and December 2003 were included in this case series. The most common manifestations of disease were respiratory and central nervous system signs. Multivariate survival analysis revealed that the only significant predictor of mortality was the presence of central nervous system signs upon presentation or during therapy. Case fatality rates in both species were high. Further investigation into effective treatment regimes is warranted. PMID:17078248

Variants of Antagonist Cryptococcus flavescens OH 182.9 with Improved Efficacy in Reducing Fusarium Head Blight in Greenhouse and Field Environments

USDA-ARS?s Scientific Manuscript database

The inclusion of biological control agent Cryptococcus flavescens OH 182.9 in the integrated management of Fusarium head blight (FHB) has potential for significantly contributing to the reduction of FHB and deoxynivalenol (DON) in wheat. Experiments were conducted to determine if liquid culture gro...

Reduction of Fusarium head blight using prothioconazole and prothioconazole-tolerant variants of the Fusarium head blight antagonist Cryptococcus flavescens OH 182.9

USDA-ARS?s Scientific Manuscript database

Integrated disease management strategies utilize a range of measures to prevent or reduce plant diseases. Combining the biological control agent Cryptococcus flavescens OH 182.9 (NRRL Y-30216) with a triazole fungicide such as prothioconazole has potential for significantly contributing to the redu...

Cryptococcus gattii: where do we go from here?

PubMed

Harris, Julie; Lockhart, Shawn; Chiller, Tom

2012-02-01

Infections caused by the emerging pathogen Cryptococcus gattii are increasing in frequency in North America. During the past decade, interest in the pathogen has continued to grow, not only in North America but also in other areas of the world where infections have recently been documented. This review synthesizes existing data and raises issues that remain to be addressed.

Management of beech stands infected by Cryptococcus fagisuga in West Germany

Treesearch

Hermann Bogenschutz

1983-01-01

Beech trees in an experimental plot in the Odenwald (southwest Germany), with different intensities of attack by Cryptococcus fagisuga Lind. since at least 1970, were observed from 1972 until 1982 in order to ascertain the role of scale insects in beech bark disease and to facilitate decisions for the management of infested stands. At the beginning...

The Epistemology of a Rule-Based Expert System: A Framework for Explanation.

DTIC Science & Technology

1982-01-01

Hypothesis e.coli cryptococcus "concluded by" 3 Rule Rule543 Rule535 predicates" 4 Hypothesis meningitis bacterial steroids a3coholic "more general" 5...the hypothesis "e.coll Is causing meningitis" before " cryptococcus is causing meningitis" Is strategic. And recalling an earlier example

A technique to screen American beech for resistance to the beech scale insect (Cryptococcus fagisuga Lind.)

Treesearch

Jennifer L. Koch; David W. Carey

2014-01-01

Beech bark disease (BBD) results in high levels of initial mortality, leaving behind survivor trees that are greatly weakened and deformed. The disease is initiated by feeding activities of the invasive beech scale insect, Cryptococcus fagisuga, which creates entry points for infection by one of the Neonectria species of fungus....

Combining mutualistic yeast and pathogenic virus - a novel method for control for codling moth control

USDA-ARS?s Scientific Manuscript database

Studies evaluated the lethal effectiveness of combining yeasts isolated from larvae of codling moth, Cydia pomonella (L.) with the codling moth granulosis virus (CpGV). Apples were treated with CpGV and three yeast species, including Metschnikowia pulcherrima Pitt and Miller, Cryptococcus tephrensis...

New secondary metabolites from bioactive extracts of the fungus Armillaria tabescens

Treesearch

H. M. T.Bandara Herath; Melissa Jacob; A. Alpus Wilson; Hamed K. Abbas; N.P. Dhammika Nanayakkara Nanayakkara

2012-01-01

Ethyl acetate extracts of Armillaria tabescens (strain JNB-OZ344) showed significant fungistatic and bacteristatic activities against several major human pathogens including Candida albicans, Cryptococcus neoformans, Escherichia coli and Mycobacterium intracellulare. Chemical analysis of these extracts led to the isolation and identification of four new compounds,...

Cryptococcus gattii Infections

PubMed Central

Chen, Sharon C.-A.; Meyer, Wieland

2014-01-01

SUMMARY Understanding of the taxonomy and phylogeny of Cryptococcus gattii has been advanced by modern molecular techniques. C. gattii probably diverged from Cryptococcus neoformans between 16 million and 160 million years ago, depending on the dating methods applied, and maintains diversity by recombining in nature. South America is the likely source of the virulent C. gattii VGII molecular types that have emerged in North America. C. gattii shares major virulence determinants with C. neoformans, although genomic and transcriptomic studies revealed that despite similar genomes, the VGIIa and VGIIb subtypes employ very different transcriptional circuits and manifest differences in virulence phenotypes. Preliminary evidence suggests that C. gattii VGII causes severe lung disease and death without dissemination, whereas C. neoformans disseminates readily to the central nervous system (CNS) and causes death from meningoencephalitis. Overall, currently available data indicate that the C. gattii VGI, VGII, and VGIII molecular types more commonly affect nonimmunocompromised hosts, in contrast to VGIV. New, rapid, cheap diagnostic tests and imaging modalities are assisting early diagnosis and enabling better outcomes of cerebral cryptococcosis. Complications of CNS infection include increased intracranial pressure, severe neurological sequelae, and development of immune reconstitution syndrome, although the mortality rate is low. C. gattii VGII isolates may exhibit higher fluconazole MICs than other genotypes. Optimal therapeutic regimens are yet to be determined; in most cases, initial therapy with amphotericin B and 5-flucytosine is recommended. PMID:25278580

Diversity and Antifungal Drug Susceptibility of Cryptococcus Isolates in Thailand.

PubMed

Worasilchai, Navaporn; Tangwattanachuleeporn, Marut; Meesilpavikkai, Kornvalee; Folba, Claudia; Kangogo, Mourine; Groß, Uwe; Weig, Michael; Bader, Oliver; Chindamporn, Ariya

2017-08-01

Yeasts of the Cryptococcus species complex are the causative agent of cryptococcosis, especially in human immunodeficiency virus (HIV) positive individuals. Cerebral or disseminated cryptococcosis has a very high mortality rate worldwide, including in Thailand. Additionally, an increasing rate of antifungal drug resistant cryptococcal isolates has been reported in several neighboring countries, complicating therapeutic approaches. To understand the situation of this infection in Thailand, we retrospectively investigated the molecular epidemiology and antifungal drug resistance in a collection of 74 clinical, 52 environmental and two veterinary isolates using the URA5-RFLP for typing and the EUCAST guideline for susceptibility testing. Where no EUCAST breakpoints (AMB and 5FC) were available, CLSI epidemiologic cutoff values were used for interpretation. Cryptococcal molecular type diversity showed most isolates were C. grubii, molecular type VNI. One clinical isolate was C. deuterogattii (mol. type VGII) and another C. grubii (mol. type VNII). One strain from environment was classified as C. grubii (mol. type VNII). No resistant strains were detected in this retrospective study for either of the antimycotics tested; however, monitoring of the epidemiology of Cryptococcus species in infected patients in Thailand needs to be continued to detect emergence of resistance. © The Author 2016. Published by Oxford University Press on behalf of The International Society for Human and Animal Mycology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Central nervous system infection due to Cryptococcus gattii sensu lato in India: Analysis of clinical features, molecular profile and antifungal susceptibility.

PubMed

Lahiri Mukhopadhyay, Shayanki; Bahubali, Veenakumari H; Manjunath, Netravathi; Swaminathan, Aarthi; Maji, Sayani; Palaniappan, Marimuthu; Parthasarathy, Satishchandra; Chandrashekar, Nagarathna

2017-11-01

Cryptococcus gattii species complex has evolved as a pathogen in the last two decades causing infection among both immunocompetent and immunocompromised hosts. We aimed to analyse the clinical features of CNS infection caused by C. gattii sensu lato, molecular and antifungal susceptibility profile of this pathogen. Cases diagnosed to have CNS cryptococcosis were included in the study. Cryptococcus recovered from patient's specimen was identified by standard protocol. Species confirmation, mating type and molecular type determination were performed by PCR based methods. Antifungal susceptibility was tested in VITEK2C to amphotericin B, 5-flucytosine, fluconazole and voriconazole. Among 199 cases, 20 (10%) were due to C. gattii, comprising of 75% cryptococcal meningitis and 25% cryptococcoma cases. Young adult males were commonly affected. Headache and vomiting were prominent symptoms and 50% were immunocompromised. Among the isolates, 75%, 20% and 5% were C. tetragattii, C. gattii sensu stricto and C. bacillisporus respectively and all had mating type α. Four (20%) isolates of C. tetragattii and the only isolate of C. bacillisporus were resistant to fluconazole. The most common species isolated from south India is C. tetragattii. The study contributes to the epidemiology of C. gattii and reiterates the need for genotyping and antifungal susceptibility testing. © 2017 Blackwell Verlag GmbH.

Process Analysis of Variables for Standardization of Antifungal Susceptibility Testing of Nonfermentative Yeasts ▿

PubMed Central

Zaragoza, Oscar; Mesa-Arango, Ana C.; Gómez-López, Alicia; Bernal-Martínez, Leticia; Rodríguez-Tudela, Juan Luis; Cuenca-Estrella, Manuel

2011-01-01

Nonfermentative yeasts, such as Cryptococcus spp., have emerged as fungal pathogens during the last few years. However, standard methods to measure their antifungal susceptibility (antifungal susceptibility testing [AST]) are not completely reliable due to the impaired growth of these yeasts in standard media. In this work, we have compared the growth kinetics and the antifungal susceptibilities of representative species of nonfermentative yeasts such as Cryptococcus neoformans, Cryptococcus gattii, Cryptococcus albidus, Rhodotorula spp., Yarrowia lipolytica, Geotrichum spp., and Trichosporon spp. The effect of the growth medium (RPMI medium versus yeast nitrogen base [YNB]), glucose concentration (0.2% versus 2%), nitrogen source (ammonium sulfate), temperature (30°C versus 35°C), shaking, and inoculum size (103, 104, and 105 cells) were analyzed. The growth rate, lag phase, and maximum optical density were obtained from each growth experiment, and after multivariate analysis, YNB-based media demonstrated a significant improvement in the growth of yeasts. Shaking, an inoculum size of 105 CFU/ml, and incubation at 30°C also improved the growth kinetics of organisms. Supplementation with ammonium sulfate and with 2% glucose did not have any effect on growth. We also tested the antifungal susceptibilities of all the isolates by the reference methods of the CLSI and EUCAST, the EUCAST method with shaking, YNB under static conditions, and YNB with shaking. MIC values obtained under different conditions showed high percentages of agreement and significant correlation coefficient values between them. MIC value determinations according to CLSI and EUCAST standards were rather complicated, since more than half of isolates tested showed a limited growth index, hampering endpoint determinations. We conclude that AST conditions including YNB as an assay medium, agitation of the plates, reading after 48 h of incubation, an inoculum size of 105 CFU/ml, and incubation at 30°C made MIC determinations easier without an overestimation of MIC values. PMID:21245438

Synergy and antagonism between iron chelators and antifungal drugs in Cryptococcus.

PubMed

Lai, Yu-Wen; Campbell, Leona T; Wilkins, Marc R; Pang, Chi Nam Ignatius; Chen, Sharon; Carter, Dee A

2016-10-01

Fungal infections remain very difficult to treat, and developing new antifungal drugs is difficult and expensive. Recent approaches therefore seek to augment existing antifungals with synergistic agents that can lower the therapeutic dose, increase efficacy and prevent resistance from developing. Iron limitation can inhibit microbial growth, and iron chelators have been employed to treat fungal infections. In this study, chequerboard testing was used to explore combinations of iron chelators with antifungal agents against pathogenic Cryptococcus spp. with the aim of determining how disruption to iron homeostasis affects antifungal susceptibility. The iron chelators ethylenediaminetetraacetic acid (EDTA), deferoxamine (DFO), deferiprone (DFP), deferasirox (DSX), ciclopirox olamine and lactoferrin (LF) were paired with the antifungal agents amphotericin B (AmB), fluconazole, itraconazole, voriconazole and caspofungin. All chelators except for DFO increased the efficacy of AmB, and significant synergy was seen between AmB and LF for all Cryptococcus strains. Addition of exogenous iron rescued cells from the antifungal effect of LF alone but could not prevent inhibition by AmB + LF, indicating that synergy was not due primarily to iron chelation but to other properties of LF that were potentiated in the presence of AmB. Significant synergy was not seen consistently for other antifungal-chelator combinations, and EDTA, DSX and DFP antagonised the activity of azole drugs in strains of Cryptococcus neoformans var. grubii. This study highlights the range of interactions that can be induced by chelators and indicates that most antifungal drugs are not enhanced by iron limitation in Cryptococcus. Copyright © 2016 Elsevier B.V. and International Society of Chemotherapy. All rights reserved.

Cryptococcus lacticolor sp. nov. and Rhodotorula oligophaga sp. nov., novel yeasts isolated from the nasal smear microbiota of Queensland koalas kept in Japanese zoological parks.

PubMed

Satoh, Kazuo; Maeda, Mari; Umeda, Yoshiko; Sugamata, Miho; Makimura, Koichi

2013-07-01

A total of 515 yeast strains were isolated from the nasal smears of Queensland koalas and their breeding environments in Japanese zoological parks between 2005 and 2012. The most frequent species in the basidiomycetous yeast biota isolated from koala nasal passages was Cryptococcus neoformans, followed by Rhodotorula minuta. R. minuta was the most frequent species in the breeding environments, while C. neoformans was rare. Seven strains representing two novel yeast species were identified. Analyses of the 26S rDNA (LSU) D1/D2 domain and nuclear ribosomal DNA internal transcribed spacer region sequences indicated that these strains represent new species with close phylogenetic relationships to Cryptococcus and Rhodotorula. A sexual state was not found for either of these two novel yeasts. Key phenotypic characters confirmed that these strains could be placed in Cryptococcus and Rhodotorula. The names Cryptococcus lacticolor sp. nov. (type strain TIMM 10013(T) = JCM 15449(T) = CBS 10915(T) = DSM 21093(T), DDBJ/EMBL/Genbank Accession No.; AB375774 (ITS) and AB375775 (26S rDNA D1/D2 region), MycoBank ID; MB 802688, Fungal Barcoding Database ID; 3174), and Rhodotorula oligophaga sp. nov. (type strain TIMM 10017(T) = JCM 18398(T) = CBS 12623(T) = DSM 25814(T), DDBJ/EMBL/Genbank Accession No.; AB702967 (ITS) and AB702967 (26S rDNA D1/D2 region), MycoBank ID; MB 802689, Fungal Barcoding Database ID; 3175) are proposed for these new species.

Population dynamics of the fusarium head blight biocontrol agent cryptococcus flavescens OH182.9 on wheat anthers and heads

USDA-ARS?s Scientific Manuscript database

Cryptococcus flavescens OH 182.9 (NRRL Y-30216) reduces Fusarium head blight (FHB) incited by Fusarium graminearum and DON contamination of grain in greenhouse and field settings. Yet little is known about the population dynamics of OH 182.9 on wheat heads and anthers from the time of inoculating he...

Tourism and Specific Risk Areas for Cryptococcus gattii, Vancouver Island, Canada

PubMed Central

Chambers, Catharine; MacDougall, Laura; Li, Min

2008-01-01

We compared travel histories of case-patients with Cryptococcus gattii infection during 1999–2006 to travel destinations of the general public on Vancouver Island, British Columbia, Canada. Findings validated and refined estimates of risk on the basis of place of residence and showed no spatial progression of risk areas on this island over time. PMID:18976570

Antagonist cryptococcus flavescens OH 182.9 3C colonization of wheat heads when applied with triazole fungicides and the effect on scab

USDA-ARS?s Scientific Manuscript database

Integrated pest management (IPM) is the best available approach for reducing Fusarium head blight (FHB; caused by Fusarium graminearum) and the mycotoxin deoxynivalenol (DON) in wheat grain. Utilizing FHB biological control agent Cryptococcus flavescens OH 182.9 (NRRL Y-30216) as part ...

Ecology of extremophile yeasts

NASA Astrophysics Data System (ADS)

Vishniac, Helen S.

1998-07-01

Capsular Cryptococcus spp. dominate in desert soils. The most extreme conditions are encountered by Cryptococcus vishniacii which dominates in the arid highlands of the Ross desert of Antarctica by virtue of its ability to grow at low temperatures, minimal nutritional requirements, tolerance of low population densities, and survival skills, although this species is neither osmo-nor halotolerant, characters which are associated with higher energy requirements.

Isolation of Cryptococcus gattii from Oregon soil and tree bark, 2010-2011.

PubMed

DeBess, Emilio; Lockhart, Shawn R; Iqbal, Naureen; Cieslak, Paul R

2014-12-21

In Oregon, human and animal infections by C. gattii were first identified in 2004. Cryptococcus gattii is considered to be an emerging non-zoonotic infection affecting animals and humans in Oregon. We report a longitudinal environmental isolation of C. gattii after an Oregon dog was diagnosed with the disease in 2009. Cryptococcus gattii was isolated twice from the same location with a span of one year between isolation dates. Cryptococcus gattii molecular types VGIIa and VGI were isolated in 2010 from soil and tree bark near the home of a 9-month-old dog which three months previously had an infection caused by C. gattii genotype VGIIa. The environment featured heavy growth of Douglas Fir trees. In 2011, a second set of soil and tree bark samples was collected in the same area and C. gattii VGIIa was again identified from the environment, along with genotypes VGIIb and VGIIc. The use of animal surveillance data to identify environmental niches of C. gattii should be considered to expand the understanding of this emerging pathogen. Understanding the ecology and how the environment and other factors might modify the existing niches is important for assessing risk and for designing measures to protect human and animal health.

Cryptococcus cyanovorans sp. nov., a basidiomycetous yeast isolated from cyanide-contaminated soil.

PubMed

Motaung, Thabiso E; Albertyn, Jacobus; Kock, Johan L F; Pohl, Carolina H

2012-05-01

Eighteen yeast strains were isolated and identified from cyanide-contaminated soil in South Africa. According to sequence-based analyses using the D1/D2 region of the large ribosomal subunit and ITS region, three of these strains were found to be identical and represent a novel species. Phylogenetic analysis based on the combined dataset of the D1/D2 and ITS regions revealed a grouping with Cryptococcus curvatus, representing a defined clade (Curvatus) in the order Trichosporonales. The three strains were demarcated from Cryptococcus curvatus by standard physiological tests such as assimilation of lactose, xylitol, 5-keto-D-gluconate, succinate and citrate as well as growth on media containing 10 % (w/v) NaCl and 5 % (w/v) glucose. In addition, it was established that these strains could utilize up to 10 mM NaCN as sole carbon source on solid media and as sole nitrogen source in liquid media. On the basis of these findings, it is suggested that the three strains represent a novel species for which the name Cryptococcus cyanovorans sp. nov. is given (type strain CBS 11948(T) = NRRL Y-48730(T)).

Neutralization of acidic drainage by Cryptococcus sp. T1 immobilized in alginate beads.

PubMed

Okai, Masahiko; Suwa, Chisato; Nagaoka, Shintaro; Obara, Nobuo; Mitsuya, Daisuke; Kurihara, Ayako; Ishida, Masami; Urano, Naoto

2017-11-01

We isolated Cryptococcus sp. T1 from Lake Tazawa's acidic water in Japan. Cryptococcus sp. T1 neutralized an acidic casamino acid solution (pH 3.0) and released ammonia from the casamino acids to aid the neutralization. The neutralization volume was estimated to be approximately 0.4 mL/h. The casamino acids' amino acids decreased (1.24→0.15 mM); ammonia increased (0.22→0.99 mM). We neutralized acidic drainage water (1 L) from a Tamagawa River neutralization plant, which was run through the column with the T1-immobilized alginate beads at a flow rate of 0.5 mL/min, and observed that the viscosity, particle size and amounts of the alginate beads affected the acidic drainage neutralization with an increase of the pH value from 5.26 to 6.61 in the last fraction. An increase in the Al concentration decreased Cryptococcus sp. T1's neutralization ability. After 48 h, the pH of acidic water with 50 mg/L Al was apparently lower than that without Al. Almost no pH increase was observed at 75 mg/L.

Cryptococcus neoformans and Cryptococcus gattii isolated from the excreta of psittaciformes in a southern Brazilian zoological garden.

PubMed

Abegg, Maxwel Adriano; Cella, Fabiana Lucila; Faganello, Josiane; Valente, Patrícia; Schrank, Augusto; Vainstein, Marilene Henning

2006-02-01

Cryptococcus neoformans, a major pathogen in immunocompromised patients, is a ubiquitous free-living fungus that can be isolated from soils, avian excreta and plant material. To further study potential saprophytic sources of this yeast in the Southern Brazilian State Rio Grande do Sul, we analyzed fecal samples from 59 species of captive birds kept in cages at a local Zoological Garden, belonging to 12 different orders. Thirty-eight environmental isolates of C. neoformans were obtained only from Psittaciformes (Psittacidae, Cacatuidae and Psittacula). Their variety and serotype were determined, and the genetic structure of the isolates was analyzed by use of the simple repetitive microsatellite specific primer M13 and the minisatellite specific primer (GACA)(4) as single primers in the PCR. The varieties were confirmed by pulsed-field gel electrophoresis (PFGE). Thirty-three isolates (87%) were from the var. grubii, serotype A, molecular type VNI and five (13%) were Cryptococcus gattii, serotype B, molecular type VGI. All the isolates were mating type alpha. Isolates were screened for some potential virulence factors. Quantitative urease production by the environmental isolates belonging to the C. gattii was similar to the values usually obtained for clinical ones.

Natural mismatch repair mutations mediate phenotypic diversity and drug resistance in Cryptococcus deuterogattii.

PubMed

Billmyre, R Blake; Clancey, Shelly Applen; Heitman, Joseph

2017-09-26

Pathogenic microbes confront an evolutionary conflict between the pressure to maintain genome stability and the need to adapt to mounting external stresses. Bacteria often respond with elevated mutation rates, but little evidence exists of stable eukaryotic hypermutators in nature. Whole genome resequencing of the human fungal pathogen Cryptococcus deuterogattii identified an outbreak lineage characterized by a nonsense mutation in the mismatch repair component MSH2. This defect results in a moderate mutation rate increase in typical genes, and a larger increase in genes containing homopolymer runs. This allows facile inactivation of genes with coding homopolymer runs including FRR1 , which encodes the target of the immunosuppresive antifungal drugs FK506 and rapamycin. Our study identifies a eukaryotic hypermutator lineage spread over two continents and suggests that pathogenic eukaryotic microbes may experience similar selection pressures on mutation rate as bacterial pathogens, particularly during long periods of clonal growth or while expanding into new environments.

Gene Network Polymorphism Illuminates Loss and Retention of Novel RNAi Silencing Components in the Cryptococcus Pathogenic Species Complex.

PubMed

Feretzaki, Marianna; Billmyre, R Blake; Clancey, Shelly Applen; Wang, Xuying; Heitman, Joseph

2016-03-01

RNAi is a ubiquitous pathway that serves central functions throughout eukaryotes, including maintenance of genome stability and repression of transposon expression and movement. However, a number of organisms have lost their RNAi pathways, including the model yeast Saccharomyces cerevisiae, the maize pathogen Ustilago maydis, the human pathogen Cryptococcus deuterogattii, and some human parasite pathogens, suggesting there may be adaptive benefits associated with both retention and loss of RNAi. By comparing the RNAi-deficient genome of the Pacific Northwest Outbreak C. deuterogattii strain R265 with the RNAi-proficient genomes of the Cryptococcus pathogenic species complex, we identified a set of conserved genes that were lost in R265 and all other C. deuterogattii isolates examined. Genetic and molecular analyses reveal several of these lost genes play roles in RNAi pathways. Four novel components were examined further. Znf3 (a zinc finger protein) and Qip1 (a homolog of N. crassa Qip) were found to be essential for RNAi, while Cpr2 (a constitutive pheromone receptor) and Fzc28 (a transcription factor) are involved in sex-induced but not mitosis-induced silencing. Our results demonstrate that the mitotic and sex-induced RNAi pathways rely on the same core components, but sex-induced silencing may be a more specific, highly induced variant that involves additional specialized or regulatory components. Our studies further illustrate how gene network polymorphisms involving known components of key cellular pathways can inform identification of novel elements and suggest that RNAi loss may have been a core event in the speciation of C. deuterogattii and possibly contributed to its pathogenic trajectory.

Unraveling Fungal Radiation Resistance Regulatory Networks through the Genome-Wide Transcriptome and Genetic Analyses of Cryptococcus neoformans.

PubMed

Jung, Kwang-Woo; Yang, Dong-Hoon; Kim, Min-Kyu; Seo, Ho Seong; Lim, Sangyong; Bahn, Yong-Sun

2016-11-29

The basidiomycetous fungus Cryptococcus neoformans has been known to be highly radiation resistant and has been found in fatal radioactive environments such as the damaged nuclear reactor at Chernobyl. To elucidate the mechanisms underlying the radiation resistance phenotype of C. neoformans, we identified genes affected by gamma radiation through genome-wide transcriptome analysis and characterized their functions. We found that genes involved in DNA damage repair systems were upregulated in response to gamma radiation. Particularly, deletion of recombinase RAD51 and two DNA-dependent ATPase genes, RAD54 and RDH54, increased cellular susceptibility to both gamma radiation and DNA-damaging agents. A variety of oxidative stress response genes were also upregulated. Among them, sulfiredoxin contributed to gamma radiation resistance in a peroxiredoxin/thioredoxin-independent manner. Furthermore, we found that genes involved in molecular chaperone expression, ubiquitination systems, and autophagy were induced, whereas genes involved in the biosynthesis of proteins and fatty acids/sterols were downregulated. Most importantly, we discovered a number of novel C. neoformans genes, the expression of which was modulated by gamma radiation exposure, and their deletion rendered cells susceptible to gamma radiation exposure, as well as DNA damage insults. Among these genes, we found that a unique transcription factor containing the basic leucine zipper domain, named Bdr1, served as a regulator of the gamma radiation resistance of C. neoformans by controlling expression of DNA repair genes, and its expression was regulated by the evolutionarily conserved DNA damage response protein kinase Rad53. Taken together, the current transcriptome and functional analyses contribute to the understanding of the unique molecular mechanism of the radiation-resistant fungus C. neoformans IMPORTANCE: Although there are no natural environments under intense radiation, some living organisms have been found to show high radiation resistance. Organisms harboring the ability of radiation resistance have unique regulatory networks to overcome this stress. Cryptococcus neoformans is one of the radiation-resistant fungi and is found in highly radioactive environments. However, it remains elusive how radiation-resistant eukaryotic microorganisms work differentially from radiation-sensitive ones. Here, we performed transcriptome analysis of C. neoformans to explore gene expression profiles after gamma radiation exposure and functionally characterized some of identified radiation resistance genes. Notably, we identified a novel regulator of radiation resistance, named Bdr1 (a bZIP TF for DNA damage response 1), which is a transcription factor (TF) that is not closely homologous to any known TF and is transcriptionally controlled by the Rad53 kinase. Therefore, our work could shed light on understanding not only the radiation response but also the radiation resistance mechanism of C. neoformans. Copyright © 2016 Jung et al.

Current trends in the prevalence of Cryptococcus gattii in the United States and Canada

PubMed Central

Espinel-Ingroff, Ana; Kidd, Sarah E

2015-01-01

The incidence of Cryptococcus gattii infections in both Canada and the United States (US) is provided in this literature review beyond the British Columbia (BC) outbreak (1999–2013). Based on a search of the literature, case reports of C. gattii human infections including the prevalent molecular genotypes causing these infections in both Canada and the US have been documented since the C. gattii outbreak in BC. The literature reveals that: i) although C. gattii infections continue to be reported in both countries, the preliminary overall number of confirmed C. gattii infections may be decreasing in both Canada and the US (~23 cases each in 2012 versus ~17 and 20 cases, respectively in 2013); ii) C. gattii genotype distribution is region-dependent; iii) C. gattii is more frequently isolated from infections in the immunocompromised host (including acquired immune deficiency syndrome [AIDS] infection) than previously expected; iv) although pulmonary disease is higher than in C. neoformans infections, central nervous system disease is also reported among patients infected with C. gattii. PMID:25999744

Protection against Experimental Cryptococcosis following Vaccination with Glucan Particles Containing Cryptococcus Alkaline Extracts.

PubMed

Specht, Charles A; Lee, Chrono K; Huang, Haibin; Tipper, Donald J; Shen, Zu T; Lodge, Jennifer K; Leszyk, John; Ostroff, Gary R; Levitz, Stuart M

2015-12-22

A vaccine capable of protecting at-risk persons against infections due to Cryptococcus neoformans and Cryptococcus gattii could reduce the substantial global burden of human cryptococcosis. Vaccine development has been hampered though, by lack of knowledge as to which antigens are immunoprotective and the need for an effective vaccine delivery system. We made alkaline extracts from mutant cryptococcal strains that lacked capsule or chitosan. The extracts were then packaged into glucan particles (GPs), which are purified Saccharomyces cerevisiae cell walls composed primarily of β-1,3-glucans. Subcutaneous vaccination with the GP-based vaccines provided significant protection against subsequent pulmonary infection with highly virulent strains of C. neoformans and C. gattii. The alkaline extract derived from the acapsular strain was analyzed by liquid chromatography tandem mass spectrometry (LC-MS/MS), and the most abundant proteins were identified. Separation of the alkaline extract by size exclusion chromatography revealed fractions that conferred protection when loaded in GP-based vaccines. Robust Th1- and Th17-biased CD4(+) T cell recall responses were observed in the lungs of vaccinated and infected mice. Thus, our preclinical studies have indicated promising cryptococcal vaccine candidates in alkaline extracts delivered in GPs. Ongoing studies are directed at identifying the individual components of the extracts that confer protection and thus would be promising candidates for a human vaccine. The encapsulated yeast Cryptococcus neoformans and its closely related sister species, Cryptococcus gattii, are major causes of morbidity and mortality, particularly in immunocompromised persons. This study reports on the preclinical development of vaccines to protect at-risk populations from cryptococcosis. Antigens were extracted from Cryptococcus by treatment with an alkaline solution. The extracted antigens were then packaged into glucan particles, which are hollow yeast cell walls composed mainly of β-glucans. The glucan particle-based vaccines elicited robust T cell immune responses and protected mice from otherwise-lethal challenge with virulent strains of C. neoformans and C. gattii. The technology used for antigen extraction and subsequent loading into the glucan particle delivery system is relatively simple and can be applied to vaccine development against other pathogens. Copyright © 2015 Specht et al.

Evaluation of a monoclonal antibody-based latex agglutination test for diagnosis of cryptococcosis: comparison with two tests using polyclonal antibodies.

PubMed Central

Temstet, A; Roux, P; Poirot, J L; Ronin, O; Dromer, F

1992-01-01

Cryptococcal antigen detection has become a routine biological test performed for patients with AIDS. The poor prognosis of cryptococcosis explains the need for reliable tests. We evaluated the performances of a newly commercialized agglutination test that uses a monoclonal antibody specific for cryptococcal capsular polysaccharide (Pastorex Cryptococcus; Sanofi-Diagnostics Pasteur, Marnes-la-Coquette, France) and compared them with those of tests that use polyclonal immune sera (Cryptococcal Antigen Latex Agglutination System, Meridian Diagnostics, Inc., Cincinnati, Ohio; and Crypto-LA, International Biological Labs Inc., Cranbury, N.J.). The sensitivities and specificities of the tests were compared by using purified polysaccharides and yeast suspensions. Clinical specimens (131 serum samples, 41 cerebrospinal fluid samples, 34 urine samples, and 19 bronchoalveolar lavage samples) from 87 human immunodeficiency virus-positive subjects with (40 patients) and without (47 patients) culture-proven cryptococcosis were retrospectively tested during a blinded study. The effect of pronase treatment of samples was assessed for Pastorex Cryptococcus and the Cryptococcal Antigen Latex Agglutination System, and the antigen titers were compared. Our results show that (i) during the screening, concordance among the three tests was 97%; (ii) the use of pronase enhanced both the sensitivities and specificities of the Pastorex Cryptococcus test; (iii) titers agreed for 67% of the cerebrospinal fluid samples and 60% of the serum samples; and (iv) cryptococcosis was detected equally well with Pastorex Cryptococcus and with the other tests, whatever the infecting serotype (A, B, or D). The meaning of in vitro sensitivity and the relationship between titers and sensitivity are discussed. The results show that Pastorex Cryptococcus is a rapid and reliable test for the detection of cryptococcal antigen in body fluids and suggest that kits cannot be used interchangeably to monitor antigen titers in patients. PMID:1400951

Interferon-γ promotes phagocytosis of Cryptococcus neoformans but not Cryptococcus gattii by murine macrophages.

PubMed

Ikeda-Dantsuji, Yurika; Ohno, Hideaki; Tanabe, Koichi; Umeyama, Takashi; Ueno, Keigo; Nagi, Minoru; Yamagoe, Satoshi; Kinjo, Yuki; Miyazaki, Yoshitsugu

2015-12-01

Among invasive fungal infections, cryptococcosis caused by inhalation of Cryptococcus neoformans or Cryptococcus gattii is particularly dangerous because it can disseminate to the central nervous system and cause life-threatening meningitis or meningoencephalitis. Previous reports described significant differences in the histopathological features of C. neoformans and C. gattii infection, such as greater pathogen proliferation and a limited macrophage response in mouse lung infected by C. gattii. To elucidate the difference in pathogenicity of these two Cryptococcus species, we investigated the interaction of C. neoformans and C. gattii with murine macrophages, the first line of host defense, by confocal laser microscopy. Only thin-capsulated, and not thick-capsulated C. neoformans and C. gattii were phagocytosed by macrophages. Preactivation with interferon-γ increased the phagocytic rate of thin-capsulated C. neoformans up to two-fold, but did not promote phagocytosis of thin-capsulated C. gattii. Lipopolysaccharide preactivation or Aspergillus fumigatus conidia co-incubation had no effect on internalization of thin-capsulated C. neoformans or C. gattii by macrophages. Phagocytosis of live thin-capsulated C. neoformans, but not that of live thin-capsulated C. gattii, induced interleukin-12 release from macrophages. However, phagocytosis of heat-killed or paraformaldehyde-fixed thin-capsulated C. neoformans did not increase IL-12 release, showing that the internalization of live yeast is important for initiating the immune response during C. neoformans-macrophage interactions. Our data suggest that macrophage response to C. gattii is limited compared with that to C. neoformans and that these results may partially explain the limited immune response and the greater pathogenicity of C. gattii. Copyright © 2015 Japanese Society of Chemotherapy and The Japanese Association for Infectious Diseases. Published by Elsevier Ltd. All rights reserved.

Molecular typing and in vitro antifungal susceptibility of Cryptococcus spp from patients in Midwest Brazil.

PubMed

Favalessa, Olivia Cometti; de Paula, Daphine Ariadne Jesus; Dutra, Valeria; Nakazato, Luciano; Tadano, Tomoko; Lazera, Marcia dos Santos; Wanke, Bodo; Trilles, Luciana; Walderez Szeszs, Maria; Silva, Dayane; Hahn, Rosane Christine

2014-08-13

Cryptococcosis is a systemic fungal infection that affects humans and animals, mainly due to Cryptococcus neoformans and Cryptococcus gattii. Following the epidemic of acquired immunodeficiency syndrome (AIDS), fungal infections by C. neoformans have become more common among immunocompromised patients. Cryptococcus gattii has primarily been isolated as a primary pathogen in healthy hosts and occurs endemically in northern and northeastern Brazil. We to perform genotypic characterization and determine the in vitro susceptibility profile to antifungal drugs of the Cryptococcus species complex isolated from HIV-positive and HIV-negative patients attended at university hospitals in Cuiabá, MT, in the Midwestern region of Brazil. Micromorphological features, chemotyping with canavanine-glycine-bromothymol blue (CGB) agar and genotyping by URA5-RFLP were used to identify the species. The antifungal drugs tested were amphotericin B, fluconazole, flucytosine, itraconazole and voriconazole. Minimum inhibitory concentrations (MICs) were determined according to the CLSI methodology M27-A3. Analysis of samples yelded C. neoformans AFLP1/VNI (17/27, 63.0%) and C. gattii AFLP6/VGII (10/27, 37.0%). The MICs ranges for the antifungal drugs were: amphotericin B (0.5-1 mg/L), fluconazole (1-16 mg/L), flucytosine (1-16 mg/L), itraconazole (0.25-0.12 mg/L) and voriconazole (0.06-0.5 mg/L). Isolates of C. neoformans AFLP1/VNI were predominant in patients with HIV/AIDS, and C. gattii VGII in HIV-negative patients. The genotypes identified were susceptible to the antifungal drugs tested. It is worth emphasizing that AFLP6/VGII is a predominant genotype affecting HIV-negative individuals in Cuiabá. These findings serve as a guide concerning the molecular epidemiology of C. neoformans and C. gattii in the State of Mato Grosso.

Heterocycle Thiazole Compounds Exhibit Antifungal Activity through Increase in the Production of Reactive Oxygen Species in the Cryptococcus neoformans-Cryptococcus gattii Species Complex.

PubMed

Sá, Nívea Pereira de; Lima, Caroline Miranda de; Lino, Cleudiomar Inácio; Barbeira, Paulo Jorge Sanches; Baltazar, Ludmila de Matos; Santos, Daniel Assis; Oliveira, Renata Barbosa de; Mylonakis, Eleftherios; Fuchs, Beth Burgwyn; Johann, Susana

2017-08-01

Human cryptococcosis can occur as a primary or opportunistic infection and develops as an acute, subacute, or chronic systemic infection involving different organs of the host. Given the limited therapeutic options and the occasional resistance to fluconazole, there is a need to develop novel drugs for the treatment of cryptococcosis. In this report, we describe promising thiazole compounds 1, 2, 3, and 4 and explore their possible modes of action against Cryptococcus To this end, we show evidence of interference in the Cryptococcus antioxidant system. The tested compounds exhibited MICs ranging from 0.25 to 2 μg/ml against Cryptococcus neoformans strains H99 and KN99α. Interestingly, the knockout strains for Cu oxidase and sarcosine oxidase were resistant to thiazoles. MIC values of thiazole compounds 1, 2, and 4 against these mutants were higher than for the parental strain. After the treatment of C. neoformans ATCC 24067 (or C. deneoformans ) and C. gattii strain L27/01 (or C. deuterogattii ) with thiazoles, we verified an increase in intracellular reactive oxygen species (ROS). Also, we verified the synergistic interactions among thiazoles and menadione, which generates superoxides, with fractional inhibitory concentrations (FICs) equal to 0.1874, 0.3024, 0.25, and 0.25 for the thiazole compounds 1, 2, 3, and 4, respectively. In addition, thiazoles exhibited antagonistic interactions with parasulphonatephenyl porphyrinato ferrate III (FeTPPS). Thus, in this work, we showed that the action of these thiazoles is related to an interference with the antioxidant system. These findings suggest that oxidative stress may be primarily related to the accumulation of superoxide radicals. Copyright © 2017 American Society for Microbiology.

Ionizing Radiation Changes the Electronic Properties of Melanin and Enhances the Growth of Melanized Fungi

PubMed Central

Dadachova, Ekaterina; Bryan, Ruth A.; Huang, Xianchun; Moadel, Tiffany; Schweitzer, Andrew D.; Aisen, Philip; Nosanchuk, Joshua D.; Casadevall, Arturo

2007-01-01

Background Melanin pigments are ubiquitous in nature. Melanized microorganisms are often the dominating species in certain extreme environments, such as soils contaminated with radionuclides, suggesting that the presence of melanin is beneficial in their life cycle. We hypothesized that ionizing radiation could change the electronic properties of melanin and might enhance the growth of melanized microorganisms. Methodology/Principal Findings Ionizing irradiation changed the electron spin resonance (ESR) signal of melanin, consistent with changes in electronic structure. Irradiated melanin manifested a 4-fold increase in its capacity to reduce NADH relative to non-irradiated melanin. HPLC analysis of melanin from fungi grown on different substrates revealed chemical complexity, dependence of melanin composition on the growth substrate and possible influence of melanin composition on its interaction with ionizing radiation. XTT/MTT assays showed increased metabolic activity of melanized C. neoformans cells relative to non-melanized cells, and exposure to ionizing radiation enhanced the electron-transfer properties of melanin in melanized cells. Melanized Wangiella dermatitidis and Cryptococcus neoformans cells exposed to ionizing radiation approximately 500 times higher than background grew significantly faster as indicated by higher CFUs, more dry weight biomass and 3-fold greater incorporation of 14C-acetate than non-irradiated melanized cells or irradiated albino mutants. In addition, radiation enhanced the growth of melanized Cladosporium sphaerospermum cells under limited nutrients conditions. Conclusions/Significance Exposure of melanin to ionizing radiation, and possibly other forms of electromagnetic radiation, changes its electronic properties. Melanized fungal cells manifested increased growth relative to non-melanized cells after exposure to ionizing radiation, raising intriguing questions about a potential role for melanin in energy capture and utilization. PMID:17520016

Chemical composition and antifungal activity of the essential oils of Lavandula viridis L'Her.

PubMed

Zuzarte, Mónica; Gonçalves, Maria José; Cavaleiro, Carlos; Canhoto, Jorge; Vale-Silva, Luís; Silva, Maria João; Pinto, Eugénia; Salgueiro, Lígia

2011-05-01

In the present work we report for what we believe to be the first time the antifungal activity and mechanism of action of the essential oils of Lavandula viridis from Portugal. The essential oils were isolated by hydrodistillation and analysed by GC and GC/MS. The MIC and the minimal lethal concentration (MLC) of the essential oil and its major compounds were determined against several pathogenic fungi. The influence of subinhibitory concentrations of the essential oil on the dimorphic transition in Candida albicans was also studied, as well as propidium iodide and FUN-1 staining of Candida albicans cells by flow cytometry following short treatments with the essential oil. The oils were characterized by a high content of oxygen-containing monoterpenes, with 1,8-cineole being the main constituent. Monoterpene hydrocarbons were present at lower concentrations. According to the determined MIC and MLC values, the dermatophytes and Cryptococcus neoformans were the most sensitive fungi (MIC and MLC values ranging from 0.32 to 0.64 µl ml⁻¹), followed by Candida species (at 0.64-2.5 µl ml⁻¹). For most of these strains, MICs were equivalent to MLCs, indicating a fungicidal effect of the essential oil. The oil was further shown to completely inhibit filamentation in Candida albicans at concentrations well below the respective MICs (as low as MIC/16). Flow cytometry results suggested a mechanism of action ultimately leading to cytoplasmic membrane disruption and cell death. Our results show that L. viridis essential oils may be useful in the clinical treatment of fungal diseases, particularly dermatophytosis and candidosis, although clinical trials are required to evaluate the practical relevance of our in vitro research.

Titan cells in Cryptococcus neoformans: Cells with a giant impact

PubMed Central

Zaragoza, Oscar; Nielsen, Kirsten

2013-01-01

Cryptococcus neoformans is a pathogenic yeast that commonly infects immunocompromised individuals, yet has developed multiple adaptation mechanisms to the host. Several virulence factors (capsule and melanin) have been known for many years. However, this yeast also possesses a morphogenetic program that is still not well characterized. Cryptococcus neoformans has the ability to dramatically enlarge its size during infection to form “titan cells” that can reach up to 100 microns in cell body diameter, in contrast to typical size cells of 5-7 microns. These titan cells pose a problem for the host because they contribute to fungal survival, dissemination to the central nervous system, and possibly even latency. In this review, we will provide an overview of these cells, covering current knowledge about their phenotypic features, mechanism of formation, and their significance during infection. PMID:23588027

Identifying the Active Microbiome Associated with Roots and Rhizosphere Soil of Oilseed Rape

PubMed Central

Mahmood, Shahid; Ekblad, Alf; Alström, Sadhna; Högberg, Nils; Finlay, Roger

2017-01-01

ABSTRACT RNA stable isotope probing and high-throughput sequencing were used to characterize the active microbiomes of bacteria and fungi colonizing the roots and rhizosphere soil of oilseed rape to identify taxa assimilating plant-derived carbon following 13CO2 labeling. Root- and rhizosphere soil-associated communities of both bacteria and fungi differed from each other, and there were highly significant differences between their DNA- and RNA-based community profiles. Verrucomicrobia, Proteobacteria, Planctomycetes, Acidobacteria, Gemmatimonadetes, Actinobacteria, and Chloroflexi were the most active bacterial phyla in the rhizosphere soil. Bacteroidetes were more active in roots. The most abundant bacterial genera were well represented in both the 13C- and 12C-RNA fractions, while the fungal taxa were more differentiated. Streptomyces, Rhizobium, and Flavobacterium were dominant in roots, whereas Rhodoplanes and Sphingomonas (Kaistobacter) were dominant in rhizosphere soil. “Candidatus Nitrososphaera” was enriched in 13C in rhizosphere soil. Olpidium and Dendryphion were abundant in the 12C-RNA fraction of roots; Clonostachys was abundant in both roots and rhizosphere soil and heavily 13C enriched. Cryptococcus was dominant in rhizosphere soil and less abundant, but was 13C enriched in roots. The patterns of colonization and C acquisition revealed in this study assist in identifying microbial taxa that may be superior competitors for plant-derived carbon in the rhizosphere of Brassica napus. IMPORTANCE This microbiome study characterizes the active bacteria and fungi colonizing the roots and rhizosphere soil of Brassica napus using high-throughput sequencing and RNA-stable isotope probing. It identifies taxa assimilating plant-derived carbon following 13CO2 labeling and compares these with other less active groups not incorporating a plant assimilate. Brassica napus is an economically and globally important oilseed crop, cultivated for edible oil, biofuel production, and phytoextraction of heavy metals; however, it is susceptible to several diseases. The identification of the fungal and bacterial species successfully competing for plant-derived carbon, enabling them to colonize the roots and rhizosphere soil of this plant, should enable the identification of microorganisms that can be evaluated in more detailed functional studies and ultimately be used to improve plant health and productivity in sustainable agriculture. PMID:28887416

Identifying the Active Microbiome Associated with Roots and Rhizosphere Soil of Oilseed Rape.

PubMed

Gkarmiri, Konstantia; Mahmood, Shahid; Ekblad, Alf; Alström, Sadhna; Högberg, Nils; Finlay, Roger

2017-11-15

RNA stable isotope probing and high-throughput sequencing were used to characterize the active microbiomes of bacteria and fungi colonizing the roots and rhizosphere soil of oilseed rape to identify taxa assimilating plant-derived carbon following 13 CO 2 labeling. Root- and rhizosphere soil-associated communities of both bacteria and fungi differed from each other, and there were highly significant differences between their DNA- and RNA-based community profiles. Verrucomicrobia , Proteobacteria , Planctomycetes , Acidobacteria , Gemmatimonadetes , Actinobacteria , and Chloroflexi were the most active bacterial phyla in the rhizosphere soil. Bacteroidetes were more active in roots. The most abundant bacterial genera were well represented in both the 13 C- and 12 C-RNA fractions, while the fungal taxa were more differentiated. Streptomyces , Rhizobium , and Flavobacterium were dominant in roots, whereas Rhodoplanes and Sphingomonas ( Kaistobacter ) were dominant in rhizosphere soil. " Candidatus Nitrososphaera" was enriched in 13 C in rhizosphere soil. Olpidium and Dendryphion were abundant in the 12 C-RNA fraction of roots; Clonostachys was abundant in both roots and rhizosphere soil and heavily 13 C enriched. Cryptococcus was dominant in rhizosphere soil and less abundant, but was 13 C enriched in roots. The patterns of colonization and C acquisition revealed in this study assist in identifying microbial taxa that may be superior competitors for plant-derived carbon in the rhizosphere of Brassica napus IMPORTANCE This microbiome study characterizes the active bacteria and fungi colonizing the roots and rhizosphere soil of Brassica napus using high-throughput sequencing and RNA-stable isotope probing. It identifies taxa assimilating plant-derived carbon following 13 CO 2 labeling and compares these with other less active groups not incorporating a plant assimilate. Brassica napus is an economically and globally important oilseed crop, cultivated for edible oil, biofuel production, and phytoextraction of heavy metals; however, it is susceptible to several diseases. The identification of the fungal and bacterial species successfully competing for plant-derived carbon, enabling them to colonize the roots and rhizosphere soil of this plant, should enable the identification of microorganisms that can be evaluated in more detailed functional studies and ultimately be used to improve plant health and productivity in sustainable agriculture. Copyright © 2017 American Society for Microbiology.

The capsule of the fungal pathogen Cryptococcus neoformans

PubMed Central

Zaragoza, Oscar; Rodrigues, Marcio L.; De Jesus, Magdia; Frases, Susana; Dadachova, Ekaterina; Casadevall, Arturo

2009-01-01

The capsule of the fungal pathogen Cryptococcus neoformans has been studied extensively in recent decades, and a large body of information is now available to the scientific community. Well-known aspects of the capsule include its structure, antigenic properties and its function as a virulence factor. The capsule is composed primarily of two polysaccharides, glucuronoxylomannan (GXM) and galactoxylomannan (GalXM), in addition to a smaller proportion of mannoproteins (MP). Most of the studies on the composition of the capsule have focused on GXM, which comprises more than 90% of the capsule's polysaccharide mass. It is GalXM, however, that is of particular scientific interest because of its immunological properties. The molecular structure of these polysaccharides is very complex and has not yet been fully elucidated. Both GXM and GalXM are high molecular mass polymers with the mass of GXM equaling roughly 10 times that of GalXM. Recent findings suggest, however, that the actual Mw might be different to what it has traditionally been thought to be. In addition to their structural roles in the polysaccharide capsule, these molecules have been associated with many deleterious effects on the immune response. Capsular components are therefore considered key virulence determinants in Cryptococcus neoformans, which has motivated their use in vaccines and made them targets for monoclonal antibody treatments. In this review we will provide an update on the current knowledge of the C. neoformans capsule, covering aspects related to its structure, synthesis, and particularly, its role as a virulence factor. PMID:19426855

Acute hind limb paralysis secondary to an extradural spinal cord Cryptococcus gattii lesion in a dog

PubMed Central

Kurach, Lindsey; Wojnarowicz, Chris; Wilkinson, Tom; Sereda, Colin

2013-01-01

A 2-year-old, spayed female, German short-haired pointer was presented with a 1-day history of non-ambulatory paraplegia with absent deep pain perception. A computed tomography scan revealed an irregular eighth thoracic vertebral body and an extradural compressive lesion. Decompression was performed and abnormal tissues were submitted for analysis. Findings were consistent with a Cryptococcus gattii infection. PMID:24155428

Diagnostic medium containing inositol, urea, and caffeic acid for selective growth of Cryptococcus neoformans.

PubMed Central

Healy, M E; Dillavou, C L; Taylor, G E

1977-01-01

An agar medium containing inositol and urea as sole carbon and nitrogen sources, caffeic acid and ferric citrate as agents for the selective pigmentation of Cryptococcus neoformans, gentamicin as a broad-spectrum bacterial antibiotic, and yeast nitrogen base without amino acids and ammonium sulfate (Difco) was tested against 137 clinical isolates, 4 survey specimens, and 11 ATCC yeast and yeast-like strains. All 28 strains of C. neoformans showed heavy growth and dark brown pigmentation after 36 h. All other tested species of Cryptococcus showed heavy growth after 36 h but only light brown pigmentation after 48 h. No growth was observed in any tested strains of Geotrichum, Pityrosporum, Rhodotorula, Saccharomyces, and Torulopsis. Only the Cryptococcus-like Candida humicola grew of the 8 species and 62 strains of Candida tested. Six of 15 strains of Trichosporon cutaneum and 1 of 2 strains of Trichosporon pullulans showed moderate growth after 48 h. Very different colonial and microscopic morphology and/or the absence of brown pigmentation easily differentiated these strains of T. cutaneum, T. pullulans, and C. humicola from C. neoformans. The growth- and pigmentation-providing characteristics of the medium were unaffected by 2 h of exposure to 254 nm of ultraviolet light. PMID:334795

Long-term survival of Cryptococcus neoformans and Cryptococcus gattii in stored environmental samples from Colombia.

PubMed

Escandón, Patricia; Castañeda, Elizabeth

2015-01-01

Both Cryptococcus neoformans and Cryptococcus gattii have been isolated from a variety of environmental sources in Colombia. To determine the viability of C. neoformans/C. gattii isolates in stored soil samples, filtrates and bird droppings from which these yeasts were previously recovered. A total of 964 samples collected between 2003 and 2009, and kept at room temperature were processed. From them, 653 samples were from trees decaying wood, 274 from soil filtrates and 37 from bird droppings. When C. neoformans or C. gattii were recovered, the molecular type of each isolate was established by PCR fingerprinting using the single primer (GTG)5. Among the processed samples, 161 isolates were recovered. From those, 81 (50.3%) corresponded to C. gattii recovered from decaying wood of Eucalyptus spp., Corymbia ficifolia, Terminalia catappa and Ficus spp. trees, and 80 (49.7%) corresponded to C. neoformans recovered from Ficus spp. and eucalyptus trees, as well as from bird droppings. The most prevalent molecular type among the C. gattii and C. neoformans isolates was VGII and VNI, respectively. The re-isolation of C. neoformans/C. gattii from 10-year stored samples suggests that these yeasts are able to keep viable in naturally colonized samples. Copyright © 2013 Revista Iberoamericana de Micología. Published by Elsevier Espana. All rights reserved.

Cryptococcus tetragattii as a major cause of cryptococcal meningitis among HIV-infected individuals in Harare, Zimbabwe.

PubMed

Nyazika, Tinashe K; Hagen, Ferry; Meis, Jacques F; Robertson, Valerie J

2016-06-01

HIV-associated cryptococcal meningitis is commonly caused by Cryptococcus neoformans, whilst infections with Cryptococcus gattii sensu lato are historically rare. Despite available studies, little is known about the occurrence of C. gattii sensu lato infections among HIV-infected individuals in Zimbabwe. In a prospective cohort, we investigated the prevalence of C. gattii sensu lato meningitis among HIV-infected patients (n = 74) in Harare, Zimbabwe. Of the 66/74 isolates confirmed by molecular characterization, 16.7% (11/66) were found to be C. gattii sensu lato and 83.3% (55/66) C. neoformans sensu stricto. From one patient two phenotypically different C. gattii sensu lato colonies were cultured. The majority (n = 9/12; 75%) of the C. gattii sensu lato isolates were Cryptococcus tetragattii (AFLP7/VGIV), which has been an infrequently reported pathogen. In-hospital mortality associated with C. gattii sensu lato was 36.4%. Our data suggests that C. tetragattii (AFLP7/VGIV) is a more common cause of disease than C. gattii sensu stricto (genotype AFLP4/VGI) among patients with HIV-associated cryptococcal meningitis in Harare, Zimbabwe and possibly underreported in sub-Saharan Africa. Copyright © 2016 The British Infection Association. Published by Elsevier Ltd. All rights reserved.

Fundamental niche prediction of the pathogenic yeasts Cryptococcus neoformans and Cryptococcus gattii in Europe.

PubMed

Cogliati, Massimo; Puccianti, Erika; Montagna, Maria T; De Donno, Antonella; Susever, Serdar; Ergin, Cagri; Velegraki, Aristea; Ellabib, Mohamed S; Nardoni, Simona; Macci, Cristina; Trovato, Laura; Dipineto, Ludovico; Rickerts, Volker; Akcaglar, Sevim; Mlinaric-Missoni, Emilija; Bertout, Sebastien; Vencà, Ana C F; Sampaio, Ana C; Criseo, Giuseppe; Ranque, Stéphane; Çerikçioğlu, Nilgün; Marchese, Anna; Vezzulli, Luigi; Ilkit, Macit; Desnos-Ollivier, Marie; Pasquale, Vincenzo; Polacheck, Itzhack; Scopa, Antonio; Meyer, Wieland; Ferreira-Paim, Kennio; Hagen, Ferry; Boekhout, Teun; Dromer, Françoise; Varma, Ashok; Kwon-Chung, Kyung J; Inácio, Joäo; Colom, Maria F

2017-10-01

Fundamental niche prediction of Cryptococcus neoformans and Cryptococcus gattii in Europe is an important tool to understand where these pathogenic yeasts have a high probability to survive in the environment and therefore to identify the areas with high risk of infection. In this study, occurrence data for C. neoformans and C. gattii were compared by MaxEnt software with several bioclimatic conditions as well as with soil characteristics and land use. The results showed that C. gattii distribution can be predicted with high probability along the Mediterranean coast. The analysis of variables showed that its distribution is limited by low temperatures during the coldest season, and by heavy precipitations in the driest season. C. neoformans var. grubii is able to colonize the same areas of C. gattii but is more tolerant to cold winter temperatures and summer precipitations. In contrast, the C. neoformans var. neoformans map was completely different. The best conditions for its survival were displayed in sub-continental areas and not along the Mediterranean coasts. In conclusion, we produced for the first time detailed prediction maps of the species and varieties of the C. neoformans and C. gattii species complex in Europe and Mediterranean area. © 2017 Society for Applied Microbiology and John Wiley & Sons Ltd.

The epidemiology of mycotic vulvovaginitis and the use of antifungal agents in suspected mycotic vulvovaginitis and its implications for clinical practice.

PubMed

Jackson, S T; Mullings, A M; Rainford, L; Miller, A

2005-06-01

Data in the Caribbean documenting the speciation of yeast associated with vulvovaginitis are lacking. The widespread use of antibiotics and increased availability of antimycotic agents, both prescribed and over-the-counter, predisposes both to a change in the epidemiologic patterns and the possible development of secondary resistance among previously susceptible yeast. This study was conducted to evaluate the aetiologic agents associated with mycotic vulvovaginitis and to review the appropriateness of prescribed antifungal therapy. Of 134 positive isolates, the most frequent yeast isolate was C. albicans accounting for 78%, C. tropicalis 10%, Prototheca wickerhamii (P. wickerhamii) 5%, C. glabrata 4%, Cryptococcus albidus (C. albidus) 2% and C. lusitaniae (1%) were also isolated. Of the positive cases, 75% were treated with antifungals, 17% with antibiotics and 8% were not treated. The azole group was the most frequently prescribed antifungal (71%). Of cases with negative yeast cultures, 83% were treated with antifungals. The presence of non-albicans Candida species and other opportunistic fungi is an important finding and combined with the pattern of therapy, represents a major challenge for future empirical therapeutic and prophylactic strategies in the treatment of mycotic vulvovaginitis.

Facile one-pot multicomponent synthesis and molecular docking studies of steroidal oxazole/thiazole derivatives with effective antimicrobial, antibiofilm and hemolytic properties.

PubMed

Ansari, Anam; Ali, Abad; Asif, Mohd; Rauf, Mohd Ahmar; Owais, Mohammad; Shamsuzzaman

2018-06-01

A series of steroidal oxazole and thiazole derivatives have been synthesized employing thiosemicarbazide/semicarbazide hydrochloride and ethyl 2-chloroacetoacetate with a simple and facile one-pot multicomponent reaction pathway. The antimicrobial activity of newly synthesized compounds were evaluated against four bacterial strains namely Gram-negative (Escherichia coliand Pseudomonas aeruginosa) and Gram-positive bacteria (Staphylococcus aureus and Listeria monocytogenes) in addition to pathogenic fungi (Candida albicans and Cryptococcus neoformans). Bioactivity assay manifested that most of the compounds exhibited good antimicrobial activity. To provide additional insight into antimicrobial activity, the compounds were also tested for their antibiofilm activity against S. aureus biofilm. Moreover, molecular docking study shows binding of compounds with amino acid residues of DNA gyrase and glucosamine-6-phosphate synthase (promising antimicrobial target) through hydrogen bonding interactions. Hemolytic activity have been also investigated to ascertain the effect of compounds over RBC lysis and results indicate good prospects for biocompatibility. The expedient synthesis of steroidal heterocycles, effective antibacterial and antifungal behavior against various clinically relevant human pathogens, promising biocompatibility offer opportunities for further modification and potential applications as therapeutic agents. Copyright © 2018 Elsevier Inc. All rights reserved.

Chemical composition and antimicrobial activity of essential oil from cones of Pinus koraiensis.

PubMed

Lee, Jeong-Ho; Yang, Hye-Young; Lee, Hong-Sub; Hong, Soon-Kwang

2008-03-01

The essential oil from the cones of Pinus koraiensis was prepared after removing the seeds, and its chemical composition analyzed using gas chromatography-mass spectrometry (GC-MS). Hydrodistillation of the P. koraiensis cones yielded 1.07% (v/w) of essential oil, which was almost three times the amount of essential oil extracted from the needles of the same plant. Moreover, the antimicrobial activities of the oil against the growth of Gram-positive bacteria, Gram-negative bacteria, and fungi were evaluated using the agar disc diffusion method and broth microdilution method. Eighty-seven components, comprising about 96.8% of the total oil, were identified. The most abundant oil components were limonene (27.90%), alpha-pinene (23.89%), beta-pinene (12.02%), 3-carene (4.95%), beta-myrcene (4.53%), isolongifolene (3.35%), (-)-bornyl acetate (2.02%), caryophyllene (1.71%), and camphene (1.54%). The essential oil was confirmed to have significant antimicrobial activities, especially against pathogenic fungal strains such as Candida glabrata YFCC 062 and Cryptococcus neoformans B 42419. Therefore, the present results indicate that the essential oil from the cones of Pinus koraiensis can be used in various ways as a nontoxic and environmentally friendly disinfectant.

Immunosuppression Related to Collagen-Vascular Disease or Its Treatment

PubMed Central

Hamilton, Carol Dukes

2005-01-01

Collagen-vascular diseases are associated with immune dysregulation and inflammation, leading to tissue destruction or compromise. Immunosuppression is more commonly associated with the drugs used to treat these disorders than with the diseases themselves. The newest agents being used to treat collagen-vascular diseases are the tumor necrosis factor (TNF)-α inhibitors. U.S. Food and Drug Administration–approved TNF-α inhibitors have differing effects on the immune system, reflecting their potency and mechanisms of action. They are particularly effective in breaking down granulomatous inflammation, which makes them effective treatment for sarcoidosis and Wegener's granulomatosis. This same property makes them likely to break down the host defense mechanism that normally contains pathogens such as mycobacteria and fungi in a dormant state, namely the physical and immunologic barrier formed by granulomas in the lung and elsewhere. The most common infection reported with the TNF-α inhibitors has been tuberculosis, which may manifest as pulmonary and/or extrapulmonary disease, with the latter being more common and severe than usual. Histoplasma capsulatum, Aspergillus, Cryptococcus neoformans, and Listeria monocytogenes have also been described in a number of cases, and their frequency is discussed. PMID:16322600

Oligonucleotide fingerprinting of rRNA genes for analysis of fungal community composition.

PubMed

Valinsky, Lea; Della Vedova, Gianluca; Jiang, Tao; Borneman, James

2002-12-01

Thorough assessments of fungal diversity are currently hindered by technological limitations. Here we describe a new method for identifying fungi, oligonucleotide fingerprinting of rRNA genes (OFRG). ORFG sorts arrayed rRNA gene (ribosomal DNA [rDNA]) clones into taxonomic clusters through a series of hybridization experiments, each using a single oligonucleotide probe. A simulated annealing algorithm was used to design an OFRG probe set for fungal rDNA. Analysis of 1,536 fungal rDNA clones derived from soil generated 455 clusters. A pairwise sequence analysis showed that clones with average sequence identities of 99.2% were grouped into the same cluster. To examine the accuracy of the taxonomic identities produced by this OFRG experiment, we determined the nucleotide sequences for 117 clones distributed throughout the tree. For all but two of these clones, the taxonomic identities generated by this OFRG experiment were consistent with those generated by a nucleotide sequence analysis. Eighty-eight percent of the clones were affiliated with Ascomycota, while 12% belonged to BASIDIOMYCOTA: A large fraction of the clones were affiliated with the genera Fusarium (404 clones) and Raciborskiomyces (176 clones). Smaller assemblages of clones had high sequence identities to the Alternaria, Ascobolus, Chaetomium, Cryptococcus, and Rhizoctonia clades.

Molecular and Nonmolecular Diagnostic Methods for Invasive Fungal Infections

PubMed Central

Arvanitis, Marios; Anagnostou, Theodora; Fuchs, Beth Burgwyn; Caliendo, Angela M.

2014-01-01

SUMMARY Invasive fungal infections constitute a serious threat to an ever-growing population of immunocompromised individuals and other individuals at risk. Traditional diagnostic methods, such as histopathology and culture, which are still considered the gold standards, have low sensitivity, which underscores the need for the development of new means of detecting fungal infectious agents. Indeed, novel serologic and molecular techniques have been developed and are currently under clinical evaluation. Tests like the galactomannan antigen test for aspergillosis and the β-glucan test for invasive Candida spp. and molds, as well as other antigen and antibody tests, for Cryptococcus spp., Pneumocystis spp., and dimorphic fungi, have already been established as important diagnostic approaches and are implemented in routine clinical practice. On the other hand, PCR and other molecular approaches, such as matrix-assisted laser desorption ionization (MALDI) and fluorescence in situ hybridization (FISH), have proved promising in clinical trials but still need to undergo standardization before their clinical use can become widespread. The purpose of this review is to highlight the different diagnostic approaches that are currently utilized or under development for invasive fungal infections and to identify their performance characteristics and the challenges associated with their use. PMID:24982319

Requirement of the isocitrate lyase gene ICL1 for VPS41-mediated starvation response in Cryptococcus neoformans.

PubMed

Xu, Zhe; Zhi, Yafei; Dong, Jianzhang; Lin, Benfeng; Ye, Di; Liu, Xiaoguang

2016-07-01

Cryptococcus neoformans is a major cause of fungal meningitis in individuals with impaired immunity. Our previous studies have shown that the VPS41 gene plays a critical role in the survival of Cryptococcus neoformans under nitrogen starvation; however, the molecular mechanisms underlying VPS41-mediated starvation response remain to be elucidated. In the present study, we show that, under nitrogen starvation, VPS41 strongly enhanced ICL1 expression in C. neoformans and that overexpression of ICL1 in the vps41 mutant dramatically suppressed its defects in starvation response due to the loss of VPS41 function. Moreover, targeted deletion of ICL1 resulted in a dramatic decline in viability of C. neoformans cells under nitrogen deprivation. Taken together, our data suggest a model in which VPS41 up-regulates ICL1 expression, directly or indirectly, to promote survival of C. neoformans under nitrogen starvation.

A Rare Presentation of Cryptococcal Meningoencephalitis in an Immunocompetent Individual

PubMed Central

Malhotra, Ashwin; Rao, Qin; Kelly, Sean; Schwartz, Danielle; Chow, Robert

2017-01-01

Cryptococcal meningoencephalitis is a leading of morbidity and mortality in immunocompromised individuals worldwide. However, there are few documented cases in immunocompetent patients. We present a rare case of disseminated Cryptococcus with progression to meningoencephalitis in an immunocompetent patient, with a possible atypical presentation. Magnetic resonance imaging of the brain and electroencephalogram to rule out brain metastasis were negative. Lumbar puncture resulted positive for Cryptococcus neoformans antigen at titers of 1:2048 and a detailed history later revealed occupational exposure to bird dander by cleaning floors and cages. Diagnosis is challenging, with delays often resulting in increased morbidity and mortality. Cerebrospinal fluid and serum Cryptococcus antigen play a key role in both diagnosis and determining treatment efficacy. Furthermore, current treatment guidelines are used for immunocompromised individuals. Due to the significant side effects of these medications, further research is needed to determine the optimal treatment duration for immunocompetent patients to minimize the need for unnecessary therapy. PMID:28959388

Ras-related C3 Botulinum Toxin Substrate (Rac) and Src Family Kinases (SFK) Are Proximal and Essential for Phosphatidylinositol 3-Kinase (PI3K) Activation in Natural Killer (NK) Cell-mediated Direct Cytotoxicity against Cryptococcus neoformans*

PubMed Central

Xiang, Richard F.; Stack, Danuta; Huston, Shaunna M.; Li, Shu Shun; Ogbomo, Henry; Kyei, Stephen K.; Mody, Christopher H.

2016-01-01

The activity of Rac in leukocytes is essential for immunity. However, its role in NK cell-mediated anti-microbial signaling remains unclear. In this study, we investigated the role of Rac in NK cell mediated anti-cryptococcal killing. We found that Cryptococcus neoformans independently activates both Rac and SFK pathways in NK cells, and unlike in tumor killing, Cryptococcus initiated a novel Rac → PI3K → Erk cytotoxicity cascade. Remarkably, Rac was not required for conjugate formation, despite its essential role in NK cytotoxicity against C. neoformans. Taken together, our data show that, unlike observations with tumor cells, NK cells use a novel Rac cytotoxicity pathway in conjunction with SFK, to kill C. neoformans. PMID:26867574

Microevolution of Serial Clinical Isolates of Cryptococcus neoformans var. grubii and C. gattii.

PubMed

Chen, Yuan; Farrer, Rhys A; Giamberardino, Charles; Sakthikumar, Sharadha; Jones, Alexander; Yang, Timothy; Tenor, Jennifer L; Wagih, Omar; Van Wyk, Marelize; Govender, Nelesh P; Mitchell, Thomas G; Litvintseva, Anastasia P; Cuomo, Christina A; Perfect, John R

2017-03-07

The pathogenic species of Cryptococcus are a major cause of mortality owing to severe infections in immunocompromised as well as immunocompetent individuals. Although antifungal treatment is usually effective, many patients relapse after treatment, and in such cases, comparative analyses of the genomes of incident and relapse isolates may reveal evidence of determinative, microevolutionary changes within the host. Here, we analyzed serial isolates cultured from cerebrospinal fluid specimens of 18 South African patients with recurrent cryptococcal meningitis. The time between collection of the incident isolates and collection of the relapse isolates ranged from 124 days to 290 days, and the analyses revealed that, during this period within the patients, the isolates underwent several genetic and phenotypic changes. Considering the vast genetic diversity of cryptococcal isolates in sub-Saharan Africa, it was not surprising to find that the relapse isolates had acquired different genetic and correlative phenotypic changes. They exhibited various mechanisms for enhancing virulence, such as growth at 39°C, adaptation to stress, and capsule production; a remarkable amplification of ERG11 at the native and unlinked locus may provide stable resistance to fluconazole. Our data provide a deeper understanding of the microevolution of Cryptococcus species under pressure from antifungal chemotherapy and host immune responses. This investigation clearly suggests a promising strategy to identify novel targets for improved diagnosis, therapy, and prognosis. IMPORTANCE Opportunistic infections caused by species of the pathogenic yeast Cryptococcus lead to chronic meningoencephalitis and continue to ravage thousands of patients with HIV/AIDS. Despite receiving antifungal treatment, over 10% of patients develop recurrent disease. In this study, we collected isolates of Cryptococcus from cerebrospinal fluid specimens of 18 patients at the time of their diagnosis and when they relapsed several months later. We then sequenced and compared the genomic DNAs of each pair of initial and relapse isolates. We also tested the isolates for several key properties related to cryptococcal virulence as well as for their susceptibility to the antifungal drug fluconazole. These analyses revealed that the relapsing isolates manifested multiple genetic and chromosomal changes that affected a variety of genes implicated in the pathogenicity of Cryptococcus or resistance to fluconazole. This application of comparative genomics to serial clinical isolates provides a blueprint for identifying the mechanisms whereby pathogenic microbes adapt within patients to prolong disease. Copyright © 2017 Chen et al.

Ancient Dispersal of the Human Fungal Pathogen Cryptococcus gattii from the Amazon Rainforest

PubMed Central

Hagen, Ferry; Ceresini, Paulo C.; Polacheck, Itzhack; Ma, Hansong; van Nieuwerburgh, Filip; Gabaldón, Toni; Kagan, Sarah; Pursall, E. Rhiannon; Hoogveld, Hans L.; van Iersel, Leo J. J.; Klau, Gunnar W.; Kelk, Steven M.; Stougie, Leen; Bartlett, Karen H.; Voelz, Kerstin; Pryszcz, Leszek P.; Castañeda, Elizabeth; Lazera, Marcia; Meyer, Wieland; Deforce, Dieter; Meis, Jacques F.; May, Robin C.; Klaassen, Corné H. W.; Boekhout, Teun

2013-01-01

Over the past two decades, several fungal outbreaks have occurred, including the high-profile ‘Vancouver Island’ and ‘Pacific Northwest’ outbreaks, caused by Cryptococcus gattii, which has affected hundreds of otherwise healthy humans and animals. Over the same time period, C. gattii was the cause of several additional case clusters at localities outside of the tropical and subtropical climate zones where the species normally occurs. In every case, the causative agent belongs to a previously rare genotype of C. gattii called AFLP6/VGII, but the origin of the outbreak clades remains enigmatic. Here we used phylogenetic and recombination analyses, based on AFLP and multiple MLST datasets, and coalescence gene genealogy to demonstrate that these outbreaks have arisen from a highly-recombining C. gattii population in the native rainforest of Northern Brazil. Thus the modern virulent C. gattii AFLP6/VGII outbreak lineages derived from mating events in South America and then dispersed to temperate regions where they cause serious infections in humans and animals. PMID:23940707

Bioconversion of volatile fatty acids derived from waste activated sludge into lipids by Cryptococcus curvatus.

PubMed

Liu, Jia; Liu, Jia-Nan; Yuan, Ming; Shen, Zi-Heng; Peng, Kai-Ming; Lu, Li-Jun; Huang, Xiang-Feng

2016-07-01

Pure volatile fatty acid (VFA) solution derived from waste activated sludge (WAS) was used to produce microbial lipids as culture medium in this study, which aimed to realize the resource recovery of WAS and provide low-cost feedstock for biodiesel production simultaneously. Cryptococcus curvatus was selected among three oleaginous yeast to produce lipids with VFAs derived from WAS. In batch cultivation, lipid contents increased from 10.2% to 16.8% when carbon to nitrogen ratio increased from about 3.5 to 165 after removal of ammonia nitrogen by struvite precipitation. The lipid content further increased to 39.6% and the biomass increased from 1.56g/L to 4.53g/L after cultivation for five cycles using sequencing batch culture (SBC) strategy. The lipids produced from WAS-derived VFA solution contained nearly 50% of monounsaturated fatty acids, including palmitic acid, heptadecanoic acid, ginkgolic acid, stearic acid, oleic acid, and linoleic acid, which showed the adequacy of biodiesel production. Copyright © 2016 Elsevier Ltd. All rights reserved.

Ancient dispersal of the human fungal pathogen Cryptococcus gattii from the Amazon rainforest.

PubMed

Hagen, Ferry; Ceresini, Paulo C; Polacheck, Itzhack; Ma, Hansong; van Nieuwerburgh, Filip; Gabaldón, Toni; Kagan, Sarah; Pursall, E Rhiannon; Hoogveld, Hans L; van Iersel, Leo J J; Klau, Gunnar W; Kelk, Steven M; Stougie, Leen; Bartlett, Karen H; Voelz, Kerstin; Pryszcz, Leszek P; Castañeda, Elizabeth; Lazera, Marcia; Meyer, Wieland; Deforce, Dieter; Meis, Jacques F; May, Robin C; Klaassen, Corné H W; Boekhout, Teun

2013-01-01

Over the past two decades, several fungal outbreaks have occurred, including the high-profile 'Vancouver Island' and 'Pacific Northwest' outbreaks, caused by Cryptococcus gattii, which has affected hundreds of otherwise healthy humans and animals. Over the same time period, C. gattii was the cause of several additional case clusters at localities outside of the tropical and subtropical climate zones where the species normally occurs. In every case, the causative agent belongs to a previously rare genotype of C. gattii called AFLP6/VGII, but the origin of the outbreak clades remains enigmatic. Here we used phylogenetic and recombination analyses, based on AFLP and multiple MLST datasets, and coalescence gene genealogy to demonstrate that these outbreaks have arisen from a highly-recombining C. gattii population in the native rainforest of Northern Brazil. Thus the modern virulent C. gattii AFLP6/VGII outbreak lineages derived from mating events in South America and then dispersed to temperate regions where they cause serious infections in humans and animals.

Isolation, Identification and Molecular Typing of Cryptococcus neoformans from Pigeon Droppings and Other Environmental Sources in Tripoli, Libya.

PubMed

Ellabib, Mohamed S; Aboshkiwa, Mohamed A; Husien, Walid M; D'Amicis, Roberta; Cogliati, Massimo

2016-08-01

Cryptococcus neoformans and C. gattii are the major cause of fungal meningitis, a potentially lethal mycosis. Since pigeon excreta and other environmental sources can be considered a significant environmental reservoir of this species in urban areas, 100 samples of pigeon excreta and 420 samples from Eucalyptus camaldulensis and Olea europaea (olive tree) around the city of Tripoli, Libya, were collected. C. neoformans was isolated and identified using standard biochemical assays from 46 samples: 34 from pigeon droppings, 3 from Eucalyptus trees and 9 from olive trees. Molecular typing revealed that all isolates from pigeon droppings belonged to molecular type VNI (C. neoformans var. grubii) and mating type αA, whereas those from trees included also the molecular type VNII and VNIII (AD hybrids). The present study reports, for the first time, information about the distribution of species, mating types and molecular types of C. neoformans/C. gattii species complex in Libya.

CRYPTOCOCCUS NEOFORMANS VAR. GRUBII-ASSOCIATED RENAL AMYLOIDOSIS CAUSING PROTEIN-LOSING NEPHROPATHY IN A RED KANGAROO (MACROPUS RUFUS).

PubMed

Thurber, Mary Irene; Gjeltema, Jenessa; Sheley, Matthew; Wack, Ray F

2017-09-01

A 10-year-old male castrated red kangaroo (Macropus rufus) presented with mandibular swelling. Examination findings included pitting edema with no dental disease evident on examination or radiographs. The results of blood work were moderate azotemia, hypoalbuminemia, and severely elevated urine protein:creatinine ratio (9.9). Radiographs showed an interstitial pattern of the caudal right lung, and an abdominal ultrasound demonstrated scant effusion. Symptomatic and empirical therapy with antibiotics, anti-inflammatory drugs, and an angiotensin-converting enzyme (ACE) inhibitor did not resolve clinical signs. Due to poor prognosis and declining quality of life, euthanasia was elected. Necropsy revealed chronic granulomatous pneumonia of the caudal right lung lobe with intralesional Cryptococcus, identified as C. neoformans var. grubii by DNA sequencing. Severe bilateral glomerular and tubulointerstitial amyloidosis induced protein-losing nephropathy, leading to tri-cavitary effusion, subcutaneous edema, and cachexia. The authors speculate that renal amyloidosis was associated with chronic cryptococcal pneumonia in this red kangaroo.

The Cryptococcus neoformans Capsule: a Sword and a Shield

PubMed Central

O'Meara, Teresa R.

2012-01-01

Summary: The human fungal pathogen Cryptococcus neoformans is characterized by its ability to induce a distinct polysaccharide capsule in response to a number of host-specific environmental stimuli. The induction of capsule is a complex biological process encompassing regulation at multiple steps, including the biosynthesis, transport, and maintenance of the polysaccharide at the cell surface. By precisely regulating the composition of its cell surface and secreted polysaccharides, C. neoformans has developed intricate ways to establish chronic infection and dormancy in the human host. The plasticity of the capsule structure in response to various host conditions also underscores the complex relationship between host and parasite. Much of this precise regulation of capsule is achieved through the transcriptional responses of multiple conserved signaling pathways that have been coopted to regulate this C. neoformans-specific virulence-associated phenotype. This review focuses on specific host stimuli that trigger the activation of the signal transduction cascades and on the downstream transcriptional responses that are required for robust encapsulation around the cell. PMID:22763631

Catalogue of the Lichenized and Lichenicolous Fungi of Montenegro

PubMed Central

Knežević, Branka; Mayrhofer, Helmut

2011-01-01

Summary The catalogue is based on a comprehensive evaluation of 169 published sources. The lichen mycota as currently known from Montenegro includes 681 species (with eight subspecies, nine varieties and one form) of lichenized fungi, 12 species of lichenicolous fungi, and nine non-lichenized fungi traditionally included in lichenological literature. PMID:21423858

A subdose of fluconazole alters the virulence of Cryptococcus gattii during murine cryptococcosis and modulates type I interferon expression.

PubMed

Fontes, Alide Caroline Lima; Bretas Oliveira, Danilo; Santos, Juliana Ribeiro Alves; Carneiro, Hellem Cristina Silva; Ribeiro, Noelly de Queiroz; Oliveira, Lorena Vívien Neves de; Barcellos, Vanessa Abreu; Paixão, Tatiane Alves; Abrahão, Jonatas Santos; Resende-Stoianoff, Maria Aparecida; Vainstein, Marilene Henning; Santos, Daniel Assis

2017-02-01

Cryptococcosis is an invasive infection caused by yeast-like fungus of the genera Cryptococcus spp. The antifungal therapy for this disease provides some toxicity and the incidence of infections caused by resistant strains increased. Thus, we aimed to assess the consequences of fluconazole subdoses during the treatment of cryptococcosis in the murine inflammatory response and in the virulence factors of Cryptococcus gattii. Mice infected with Cryptococcus gattii were treated with subdoses of fluconazole. We determined the behavior of mice and type 1 interferon expression during the treatment; we also studied the virulence factors and susceptibility to fluconazole for the colonies recovered from the animals. A subdose of fluconazole prolonged the survival of mice, but the morbidity of cryptococcosis was higher in treated animals. These data were linked to the increase in: (i) fluconazole minimum inhibitory concentration, (ii) capsule size and (iii) melanization of C. gattii, which probably led to the increased expression of type I interferons in the brains of mice but not in the lungs. In conclusion, a subdose of fluconazole altered fungal virulence factors and susceptibility to this azole, leading to an altered inflammatory host response and increased morbidity. © The Author 2016. Published by Oxford University Press on behalf of The International Society for Human and Animal Mycology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Synergistic Effect of Sarocladium sp. and Cryptococcus sp. Co-Culture on Crude Oil Biodegradation and Biosurfactant Production.

PubMed

Kamyabi, Aliyeh; Nouri, Hoda; Moghimi, Hamid

2017-05-01

This study was conducted to evaluate the co-culture ability of two yeast (Sarocladium sp. and Cryptococcus sp.) isolates as compared to their individual cultures in surfactant production and oil degradation. The results showed that individual culture of each strain was capable of producing surfactant, degrading oil, and pyrene; also, a synergistic effect was observed when a co-culture was applied. Oil removal and biomass production were 28 and 35% higher in the co-culture than in individual cultures, respectively. To investigate the synergistic effects of mix culture on oil degradation, the surface tension, emulsification activity (EA), and cell surface hydrophobicity of individual and co-culture were studied. A comparison between the produced biosurfactant and chemical surfactants showed that individual culture of each yeast strain could reduce the surface tension like SDS and about 10% better than Tween 80. The results showed that the microbial consortium could reduce the surface tension more, by 10 and 20%, than SDS and Tween 80, respectively. Both individual cultures of Sarocladium sp. and Cryptococcus sp. showed good emulsification activity (0.329 and 0.412, respectively) when compared with a non-inoculated medium. Emulsification activity measurement for the two yeast mix cultures showed an excellent 33 and 67% increase as compared to the individual culture of Sarocladium sp. and Cryptococcus sp., respectively. The cell surface hydrophobicity of Sarocladium sp. and Cryptococcus sp. increased (38 and 85%) when the cells were treated with pyrene as a hydrophobic substrate for four generations. Finally, a 40% increase for pyrene degradation was measured in a co-culture of the two yeast mix culture. According to the results of the present study, the co-culture system exhibited better performance and this study will enhance the understanding of the synergistic effects of yeast co-culture on oil degradation.

Cryptococcus gattii in North American Pacific Northwest: whole-population genome analysis provides insights into species evolution and dispersal.

PubMed

Engelthaler, David M; Hicks, Nathan D; Gillece, John D; Roe, Chandler C; Schupp, James M; Driebe, Elizabeth M; Gilgado, Felix; Carriconde, Fabian; Trilles, Luciana; Firacative, Carolina; Ngamskulrungroj, Popchai; Castañeda, Elizabeth; Lazera, Marcia dos Santos; Melhem, Marcia S C; Pérez-Bercoff, Asa; Huttley, Gavin; Sorrell, Tania C; Voelz, Kerstin; May, Robin C; Fisher, Matthew C; Thompson, George R; Lockhart, Shawn R; Keim, Paul; Meyer, Wieland

2014-07-15

The emergence of distinct populations of Cryptococcus gattii in the temperate North American Pacific Northwest (PNW) was surprising, as this species was previously thought to be confined to tropical and semitropical regions. Beyond a new habitat niche, the dominant emergent population displayed increased virulence and caused primary pulmonary disease, as opposed to the predominantly neurologic disease seen previously elsewhere. Whole-genome sequencing was performed on 118 C. gattii isolates, including the PNW subtypes and the global diversity of molecular type VGII, to better ascertain the natural source and genomic adaptations leading to the emergence of infection in the PNW. Overall, the VGII population was highly diverse, demonstrating large numbers of mutational and recombinational events; however, the three dominant subtypes from the PNW were of low diversity and were completely clonal. Although strains of VGII were found on at least five continents, all genetic subpopulations were represented or were most closely related to strains from South America. The phylogenetic data are consistent with multiple dispersal events from South America to North America and elsewhere. Numerous gene content differences were identified between the emergent clones and other VGII lineages, including genes potentially related to habitat adaptation, virulence, and pathology. Evidence was also found for possible gene introgression from Cryptococcus neoformans var. grubii that is rarely seen in global C. gattii but that was present in all PNW populations. These findings provide greater understanding of C. gattii evolution in North America and support extensive evolution in, and dispersal from, South America. Importance: Cryptococcus gattii emerged in the temperate North American Pacific Northwest (PNW) in the late 1990s. Beyond a new environmental niche, these emergent populations displayed increased virulence and resulted in a different pattern of clinical disease. In particular, severe pulmonary infections predominated in contrast to presentation with neurologic disease as seen previously elsewhere. We employed population-level whole-genome sequencing and analysis to explore the genetic relationships and gene content of the PNW C. gattii populations. We provide evidence that the PNW strains originated from South America and identified numerous genes potentially related to habitat adaptation, virulence expression, and clinical presentation. Characterization of these genetic features may lead to improved diagnostics and therapies for such fungal infections. The data indicate that there were multiple recent introductions of C. gattii into the PNW. Public health vigilance is warranted for emergence in regions where C. gattii is not thought to be endemic. Copyright © 2014 Engelthaler et al.

Interleukin-6 production by human monocytes stimulated with Cryptococcus neoformans components.

PubMed Central

Delfino, D; Cianci, L; Lupis, E; Celeste, A; Petrelli, M L; Curró, F; Cusumano, V; Teti, G

1997-01-01

In order to ascertain if Cryptococcus neoformans components can induce interleukin-6 (IL-6) production, we stimulated human whole blood with purified capsular products. Their potencies in stimulating IL-6 release were mannoproteins > galactoxylomannan = glucuronoxylomannan > alpha(1-3)glucan. IL-6 production was tumor necrosis factor alpha independent and required the presence of monocytes and plasma. Since IL-6 can stimulate replication of the human immunodeficiency virus in monocytic cells, these findings may be clinically relevant. PMID:9169790

Control of Cryptococcus neoformans in nature by biotic factors.

PubMed

Ruiz, A; Neilson, J B; Bulmer, G S

1982-03-01

Two bacterial species (Pseudomonas aeruginosa and Bacillus subtilis) isolated from pigeon droppings, displayed anti Cryptococcus neoformans activity on 4 of 6 media and sterilized pigeon droppings. Acanthamoeba palestinensis trophozoites isolated from pigeon droppings ingested and killed 99.9% of C neoformans cells after 7 days of incubation. Mites and sow bugs (Metoponorthus pruinosus) isolated from pigeon droppings appear to be fungivorous. These findings suggest that many organisms that occur in pigeon droppings influence C. neoformans persistence, reproduction, morphology and distribution in nature.

Isolation of Cryptococcus gattii from a Castanopsis argyrophylla tree hollow (Mai-Kaw), Chiang Mai, Thailand.

PubMed

Khayhan, Kantarawee; Hagen, Ferry; Norkaew, Treepradab; Puengchan, Tanpalang; Boekhout, Teun; Sriburee, Pojana

2017-04-01

The pathogenic yeast Cryptococcus gattii was isolated from a tree hollow of a Castanopsis argyrophylla King ex Hook.f. (Fagaceae) in Chiang Mai, Thailand. Molecular characterization with amplified fragment length polymorphism analysis and multi-locus sequence typing showed that this isolate belonged to genotype AFLP4/VGI representing C. gattii sensu stricto. Subsequent comparison of the environmental isolate with those from clinical samples from Thailand showed that they grouped closely together in a single cluster.

Cryptococcemia. An analysis of 28 cases with emphasis on the clinical outcome and its etiologic agent.

PubMed

Pasqualotto, Alessandro Comarú; Bittencourt Severo, Cecília; de Mattos Oliveira, Flávio; Severo, Luiz Carlos

2004-09-01

Clinical protocols of 28 cases of cryptococcemia studied between April 1995 and November 2002 were reviewed. The varieties of Cryptococcus neorformans, the underlying disease, and the severity and outcome of the disease were emphasized. Most patients were immunossupressed (89.3% with AIDS) and Cryptococcus neoformans var. grubii was the main recovered variety (92.8%). Regardless of antifungal treatment, in-hospital mortality was 41% strongly associated with APACHE II score, >14 (p<0.01).

First case of disseminated cryptococcosis in a Gorilla gorilla.

PubMed

Mischnik, Alexander; Stockklausner, Julia; Hohneder, Nicole; Jensen, Henrik E; Zimmermann, Stefan; Reuss, David E; Rickerts, Volker; Tintelnot, Kathrin; Stockklausner, Clemens

2014-11-01

In humans, Cryptococcus mainly infects individuals with HIV infection or other types of immunosuppression. Here, we report the first case of disseminated cryptococcosis in a simian immunodeficiency virus-negative 27-year-old female Gorilla gorilla presenting with lethargy, progressive weight loss and productive cough. The diagnosis was confirmed by positive lung biopsy culture, serum cryptococcal antigen, and cerebral histopathology demonstrating encapsulated yeasts. Molecular characterisation of lung culture isolate yielded Cryptococcus neoformans var. grubii. An immune-deficiency could not be demonstrated. © 2014 Blackwell Verlag GmbH.

The Case for Adopting the "Species Complex" Nomenclature for the Etiologic Agents of Cryptococcosis.

PubMed

Kwon-Chung, Kyung J; Bennett, John E; Wickes, Brian L; Meyer, Wieland; Cuomo, Christina A; Wollenburg, Kurt R; Bicanic, Tihana A; Castañeda, Elizabeth; Chang, Yun C; Chen, Jianghan; Cogliati, Massimo; Dromer, Françoise; Ellis, David; Filler, Scott G; Fisher, Matthew C; Harrison, Thomas S; Holland, Steven M; Kohno, Shigeru; Kronstad, James W; Lazera, Marcia; Levitz, Stuart M; Lionakis, Michail S; May, Robin C; Ngamskulrongroj, Popchai; Pappas, Peter G; Perfect, John R; Rickerts, Volker; Sorrell, Tania C; Walsh, Thomas J; Williamson, Peter R; Xu, Jianping; Zelazny, Adrian M; Casadevall, Arturo

2017-01-01

Cryptococcosis is a potentially lethal disease of humans/animals caused by Cryptococcus neoformans and Cryptococcus gattii . Distinction between the two species is based on phenotypic and genotypic characteristics. Recently, it was proposed that C. neoformans be divided into two species and C. gattii into five species based on a phylogenetic analysis of 115 isolates. While this proposal adds to the knowledge about the genetic diversity and population structure of cryptococcosis agents, the published genotypes of 2,606 strains have already revealed more genetic diversity than is encompassed by seven species. Naming every clade as a separate species at this juncture will lead to continuing nomenclatural instability. In the absence of biological differences between clades and no consensus about how DNA sequence alone can delineate a species, we recommend using " Cryptococcus neoformans species complex" and " C. gattii species complex" as a practical intermediate step, rather than creating more species. This strategy recognizes genetic diversity without creating confusion.

Cloning, molecular characterization and heterologous expression of AMY1, an alpha-amylase gene from Cryptococcus flavus.

PubMed

Galdino, Alexsandro S; Ulhoa, Cirano J; Moraes, Lídia Maria P; Prates, Maura V; Bloch, Carlos; Torres, Fernando A G

2008-03-01

A Cryptococcus flavus gene (AMY1) encoding an extracellular alpha-amylase has been cloned. The nucleotide sequence of the cDNA revealed an ORF of 1896 bp encoding for a 631 amino acid polypeptide with high sequence identity with a homologous protein isolated from Cryptococcus sp. S-2. The presence of four conserved signature regions, (I) (144)DVVVNH(149), (II) (235)GLRIDSLQQ(243), (III) (263)GEVFN(267), (IV) (327)FLENQD(332), placed the enzyme in the GH13 alpha-amylase family. Furthermore, sequence comparison suggests that the C. flavusalpha-amylase has a C-terminal starch-binding domain characteristic of the CBM20 family. AMY1 was successfully expressed in Saccharomyces cerevisiae. The time course of amylase secretion in S. cerevisiae resulted in a maximal extracellular amylolytic activity (3.93 U mL(-1)) at 60 h of incubation. The recombinant protein had an apparent molecular mass similar to the native enzyme (c. 67 kDa), part of which was due to N-glycosylation.

[Cyptococcus gattii isolated from a cheetah (Acinonyx jubatus) in the National Zoo of Cuba].

PubMed

Polo Leal, Jorge Luis; Fernández Andreu, Carlos Manuel; Martínez Machín, Gerardo; Illnait Zaragozi, María Teresa; Perurena Lancha, Mayda Rosa

2010-01-01

Cryptoccosis--systemic mycosis caused by Cryptococcus species--has considerably raised its incidence in the last years, mainly associated with the human immunodeficiency virus infection. It has also been described in animals, but rare cases. a case of a female cheetah (Acinonyx jubatus) kept in the Nacional Zoo of Havana was presented. The animal came from South Africa. She began losing weight, and suffering asthenia, anorexia and breathing problems with abundant nasal secretion. mycological testing of these secretions disclosed the presence of serotype B Cryptococcus gattii. Because of the origin and captive condition of the animal, it was believed that the infection had been latent for 16 months at least. up to the present, in Cuba, all clinical Cryptococcus isolates were C. neoformans var. grubii, so it is considered that the infection was caught in the country of origin of the female cheetah. This is the first C. gattii isolate in Cuba from an animal coming from South Africa where this fungus is endemic.

Case report: false negative serum cryptococcal latex agglutination test in a patient with disseminated cryptococcal disease.

PubMed

Navabi, Nazlee; Montebatsi, Milton; Scott, Michelle; Gluckman, Stephen J; Reid, Michael J A

2015-01-01

A case of false-negative serum latex agglutination cryptococcal antigen (CRAG) test in a 45-year-old HIV-positive male with Cryptococcus-positive culture is described. The patient was presented to a hospital in Botswana, with breathlessness and a diffuse papular rash. His CD4 count was 25 cells/μL. Despite the suspicion for disseminated cryptococcal disease, an initial serum CRAG latex test was negative. Results of subsequent Indian ink staining, culture of cerebrospinal fluid and skin scrapings, and serum lateral flow immunoassay (LFA) were all positive for Cryptococcus neoformans. There are several possible explanations for the false-negative CRAG latex test. Given the positive LFA result, we speculate that disease may have been caused by Cryptococcus gattii, which is estimated to be responsible for between 15% and 30% of all cryptococcal diseases in Botswana. Reduced sensitivity of CRAG latex assays for detecting C gattii may lead to underdiagnosis of cryptococcal infection. © The Author(s) 2014.

Systemic fungal infections in patients with human inmunodeficiency virus.

PubMed

Rodríguez-Cerdeira, C; Arenas, R; Moreno-Coutiño, G; Vásquez, E; Fernández, R; Chang, P

2014-01-01

Histoplasmosis is a systemic infection caused by the dimorphic fungus Histoplasma capsulatum. In immunocompromised patients, primary pulmonary infection can spread to the skin and meninges. Clinical manifestations appear in patients with a CD4(+) lymphocyte count of less than 150 cells/μL. Coccidioidomycosis is a systemic mycosis caused by Coccidioides immitis and Coccidioides posadasii. It can present as diffuse pulmonary disease or as a disseminated form primarily affecting the central nervous system, the bones, and the skin. Cryptococcosis is caused by Cryptococcus neoformans (var. neoformans and var. grubii) and Cryptococcus gattii, which are members of the Cryptococcus species complex and have 5 serotypes: A, B, C, D, and AD. It is a common opportunistic infection in patients with human immunodeficiency virus (HIV)/AIDS, even those receiving antiretroviral therapy. Histopathologic examination and culture of samples from any suspicious lesions are essential for the correct diagnosis of systemic fungal infections in patients with HIV/AIDS. Copyright © 2011 Elsevier España, S.L. and AEDV. All rights reserved.

Importance of Resolving Fungal Nomenclature: the Case of Multiple Pathogenic Species in the Cryptococcus Genus.

PubMed

Hagen, Ferry; Lumbsch, H Thorsten; Arsic Arsenijevic, Valentina; Badali, Hamid; Bertout, Sebastien; Billmyre, R Blake; Bragulat, M Rosa; Cabañes, F Javier; Carbia, Mauricio; Chakrabarti, Arunaloke; Chaturvedi, Sudha; Chaturvedi, Vishnu; Chen, Min; Chowdhary, Anuradha; Colom, Maria-Francisca; Cornely, Oliver A; Crous, Pedro W; Cuétara, Maria S; Diaz, Mara R; Espinel-Ingroff, Ana; Fakhim, Hamed; Falk, Rama; Fang, Wenjie; Herkert, Patricia F; Ferrer Rodríguez, Consuelo; Fraser, James A; Gené, Josepa; Guarro, Josep; Idnurm, Alexander; Illnait-Zaragozi, María-Teresa; Khan, Ziauddin; Khayhan, Kantarawee; Kolecka, Anna; Kurtzman, Cletus P; Lagrou, Katrien; Liao, Wanqing; Linares, Carlos; Meis, Jacques F; Nielsen, Kirsten; Nyazika, Tinashe K; Pan, Weihua; Pekmezovic, Marina; Polacheck, Itzhack; Posteraro, Brunella; de Queiroz Telles, Flavio; Romeo, Orazio; Sánchez, Manuel; Sampaio, Ana; Sanguinetti, Maurizio; Sriburee, Pojana; Sugita, Takashi; Taj-Aldeen, Saad J; Takashima, Masako; Taylor, John W; Theelen, Bart; Tomazin, Rok; Verweij, Paul E; Wahyuningsih, Retno; Wang, Ping; Boekhout, Teun

2017-01-01

Cryptococcosis is a major fungal disease caused by members of the Cryptococcus gattii and Cryptococcus neoformans species complexes. After more than 15 years of molecular genetic and phenotypic studies and much debate, a proposal for a taxonomic revision was made. The two varieties within C. neoformans were raised to species level, and the same was done for five genotypes within C. gattii . In a recent perspective (K. J. Kwon-Chung et al., mSphere 2:e00357-16, 2017, https://doi.org/10.1128/mSphere.00357-16), it was argued that this taxonomic proposal was premature and without consensus in the community. Although the authors of the perspective recognized the existence of genetic diversity, they preferred the use of the informal nomenclature " C. neoformans species complex" and " C. gattii species complex." Here we highlight the advantage of recognizing these seven species, as ignoring these species will impede deciphering further biologically and clinically relevant differences between them, which may in turn delay future clinical advances.

Molecular types of Cryptococcus gattii/Cryptococcus neoformans species complex from clinical and environmental sources in Nairobi, Kenya.

PubMed

Kangogo, Mourine; Bader, Oliver; Boga, Hamadi; Wanyoike, Wanjiru; Folba, Claudia; Worasilchai, Navaporn; Weig, Michael; Groß, Uwe; Bii, Christine C

2015-11-01

Cryptococcal meningitis infections cause high mortality rates among HIV-infected patients in Sub-Saharan Africa. The high incidences of cryptococcal infections may be attributed to common environmental sources which, if identified, could lead to institution of appropriate control strategies. To determine the genotypes of Cryptococcus gattii/C. neoformans- species complex from Nairobi, Kenya, 123 clinical and environmental isolates were characterised. Typing was done using orotidine monophosphate pyrophosphorylase (URA5) gene restriction fragment length polymorphism (URA5-RFLP). The majority of the isolates [105/123; 85.4%] were C. neoformans genotype (AFLPI/VNI) and 1.6% AFLP1A/VNB/VNII, whereas (13%) were C. gattii (AFLP4/VGI). This is the first report on the genotypes of C. gattii/C. neoformans species complex from clinical and environmental sources in Nairobi, Kenya and the isolation of C. gattii genotype AFLP4/VGI from the environment in Kenya. © 2015 Blackwell Verlag GmbH.

Neuroinfections caused by fungi.

PubMed

Góralska, Katarzyna; Blaszkowska, Joanna; Dzikowiec, Magdalena

2018-05-21

Fungal infections of the central nervous system (FIs-CNS) have become significantly more common over the past 2 decades. Invasion of the CNS largely depends on the immune status of the host and the virulence of the fungal strain. Infections with fungi cause a significant morbidity in immunocompromised hosts, and the involvement of the CNS may lead to fatal consequences. One hundred and thirty-five articles on fungal neuroinfection in PubMed, Google Scholar, and Cochrane databases were selected for review using the following search words: "fungi and CNS mycoses", CNS fungal infections", "fungal brain infections", " fungal cerebritis", fungal meningitis", "diagnostics of fungal infections", and "treatment of CNS fungal infections". All were published in English with the majority in the period 2000-2018. This review focuses on the current knowledge of the epidemiology, clinical presentations, diagnosis, and treatment of selected FIs-CNS. The FIs-CNS can have various clinical presentations, mainly meningitis, encephalitis, hydrocephalus, cerebral abscesses, and stroke syndromes. The etiologic factors of neuroinfections are yeasts (Cryptococcus neoformans, Candida spp., Trichosporon spp.), moniliaceous moulds (Aspergillus spp., Fusarium spp.), Mucoromycetes (Mucor spp., Rhizopus spp.), dimorphic fungi (Blastomyces dermatitidis, Coccidioides spp., Histoplasma capsulatum), and dematiaceous fungi (Cladophialophora bantiana, Exophiala dermatitidis). Their common route of transmission is inhalation or inoculation from trauma or surgery, with subsequent hematogenous or contiguous spread. As the manifestations of FIs-CNS are often non-specific, their diagnosis is very difficult. A fast identification of the etiological factor of neuroinfection and the application of appropriate therapy are crucial in preventing an often fatal outcome. The choice of effective drug depends on its extent of CNS penetration and spectrum of activity. Pharmaceutical formulations of amphotericin B (AmB) (among others, deoxycholate-AmBd and liposomal L-AmB) have relatively limited distribution in the cerebrospinal fluid (CSF); however, their detectable therapeutic concentrations in the CNS makes them recommended drugs for the treatment of cryptococcal meningoencephalitis (AmBd with flucytosine) and CNS candidiasis (L-AmB) and mucormycosis (L-AmB). Voriconazole, a moderately lipophilic molecule with good CNS penetration, is recommended in the first-line therapy of CNS aspergillosis. Other triazoles, such as posaconazole and itraconazole, with negligible concentrations in the CSF are not considered effective drugs for therapy of CNS fungal neuroinfections. In contrast, clinical data have shown that a novel triazole, isavuconazole, achieved considerable efficacy for the treatment of some fungal neuroinfections. Echinocandins with relatively low or undetectable concentrations in the CSF do not play meaningful role in the treatment of FIs-CNS. Although the number of fungal species causing CNS mycosis is increasing, only some possess well-defined treatment standards (e.g., cryptococcal meningitis and CNS aspergillosis). The early diagnosis of fungal infection, accompanied by identification of the etiological factor, is needed to allow the selection of effective therapy in patients with FIs-CNS and limit their high mortality.

Calcineurin Governs Thermotolerance and Virulence of Cryptococcus gattii

PubMed Central

Chen, Ying-Lien; Lehman, Virginia N.; Lewit, Yonathan; Averette, Anna F.; Heitman, Joseph

2013-01-01

The pathogenic yeast Cryptococcus gattii, which is causing an outbreak in the Pacific Northwest region of North America, causes life-threatening pulmonary infections and meningoencephalitis in healthy individuals, unlike Cryptococcus neoformans, which commonly infects immunocompromised patients. In addition to a greater predilection for C. gattii to infect healthy hosts, the C. gattii genome sequence project revealed extensive chromosomal rearrangements compared with C. neoformans, showing genomic differences between the two Cryptococcus species. We investigated the roles of C. gattii calcineurin in three molecular types: VGIIa (R265), VGIIb (R272), and VGI (WM276). We found that calcineurin exhibits a differential requirement for growth on solid medium at 37°, as calcineurin mutants generated from R265 were more thermotolerant than mutants from R272 and WM276. We demonstrated that tolerance to calcineurin inhibitors (FK506, CsA) at 37° is linked with the VGIIa molecular type. The calcineurin mutants from the R272 background showed the most extensive growth and morphological defects (multivesicle and larger ring-like cells), as well as increased fluconazole susceptibility. Our cellular architecture examination showed that C. gattii and C. neoformans calcineurin mutants exhibit plasma membrane disruptions. Calcineurin in the C. gattii VGII molecular type plays a greater role in controlling cation homeostasis compared with that in C. gattii VGI and C. neoformans H99. Importantly, we demonstrate that C. gattii calcineurin is essential for virulence in a murine inhalation model, supporting C. gattii calcineurin as an attractive antifungal drug target. PMID:23450261

Disseminated, histologically confirmed Cryptococcus spp infection in a domestic ferret.

PubMed

Eshar, David; Mayer, Jörg; Parry, Nicola M; Williams-Fritze, Misty J; Bradway, Daniel S

2010-04-01

A 4-year-old castrated male domestic ferret from central Massachusetts was evaluated for weight loss over a 1.5-month period and for 2 days of retching, diarrhea, and signs of lethargy. It had been housed indoors, with 2 other ferrets, 2 cats, and humans that lacked signs or symptoms of disease. Physical examination revealed a thin body condition, tachypnea, an increase in respiratory effort, and retching. Splenomegaly was detected during abdominal palpation. Clinicopathologic analysis revealed lymphopenia, lactic acidosis, hypoglycemia, hypocalcemia, hypoalbuminemia, and hyperglobulinemia. A pulmonary bronchointerstitial pattern was evident on radiographs, and abdominal ultrasonography revealed a suspected pancreatic mass and mesenteric lymphadenopathy. After 2 weeks of medical treatment and once clinical signs resolved, an exploratory laparotomy was performed and a lymph node biopsy specimen was collected. Histologic evaluation of the specimen revealed Cryptococcus-like organisms. Antifungal treatment was initiated with itraconazole (PO) and amphotericin B (IV). The ferret died after 2 days of treatment. A full necropsy was performed, revealing multicentric cryptococcosis affecting the lungs, brain, spleen, and multiple lymph nodes. Paraffin-embedded, formalin-fixed lung tissue was submitted for DNA extraction, and the organism was identified as Cryptococcus neoformans var grubii. To the authors' knowledge, this is the first report of disseminated cryptococcosis in a North American ferret. This case is unique in that the ferret lived indoors, in a geographic region in which reports of cryptococcosis are rare. The genotyping technique used to identify the Cryptococcus strain can aid in better understanding the epidemiology of cryptococcosis.

Cryptococcus neoformans mates on pigeon guano: implications for the realized ecological niche and globalization.

PubMed

Nielsen, Kirsten; De Obaldia, Anna L; Heitman, Joseph

2007-06-01

The ecological niche that a species can occupy is determined by its resource requirements and the physical conditions necessary for survival. The niche to which an organism is most highly adapted is the realized niche, whereas the complete range of habitats that an organism can occupy represents the fundamental niche. The growth and development of Cryptococcus neoformans and Cryptococcus gattii on pigeon guano were examined to determine whether these two species occupy the same or different ecological niches. C. neoformans is a cosmopolitan pathogenic yeast that infects predominantly immunocompromised individuals, exists in two varieties (grubii [serotype A] and neoformans [serotype D]), and is commonly isolated from pigeon guano worldwide. By contrast, C. gattii often infects immunocompetent individuals and is associated with geographically restricted environments, most notably, eucalyptus trees. Pigeon guano supported the growth of both species, and a brown pigment related to melanin, a key virulence factor, was produced. C. neoformans exhibited prolific mating on pigeon guano, whereas C. gattii did not. The observations that C. neoformans completes the life cycle on pigeon guano but that C. gattii does not indicates that pigeon guano could represent the realized ecological niche for C. neoformans. Because C. gattii grows on pigeon guano but cannot sexually reproduce, pigeon guano represents a fundamental but not a realized niche for C. gattii. Based on these studies, we hypothesize that an ancestral Cryptococcus strain gained the ability to sexually reproduce in pigeon guano and then swept the globe.

Cryptococcus neoformans Mates on Pigeon Guano: Implications for the Realized Ecological Niche and Globalization▿

PubMed Central

Nielsen, Kirsten; De Obaldia, Anna L.; Heitman, Joseph

2007-01-01

The ecological niche that a species can occupy is determined by its resource requirements and the physical conditions necessary for survival. The niche to which an organism is most highly adapted is the realized niche, whereas the complete range of habitats that an organism can occupy represents the fundamental niche. The growth and development of Cryptococcus neoformans and Cryptococcus gattii on pigeon guano were examined to determine whether these two species occupy the same or different ecological niches. C. neoformans is a cosmopolitan pathogenic yeast that infects predominantly immunocompromised individuals, exists in two varieties (grubii [serotype A] and neoformans [serotype D]), and is commonly isolated from pigeon guano worldwide. By contrast, C. gattii often infects immunocompetent individuals and is associated with geographically restricted environments, most notably, eucalyptus trees. Pigeon guano supported the growth of both species, and a brown pigment related to melanin, a key virulence factor, was produced. C. neoformans exhibited prolific mating on pigeon guano, whereas C. gattii did not. The observations that C. neoformans completes the life cycle on pigeon guano but that C. gattii does not indicates that pigeon guano could represent the realized ecological niche for C. neoformans. Because C. gattii grows on pigeon guano but cannot sexually reproduce, pigeon guano represents a fundamental but not a realized niche for C. gattii. Based on these studies, we hypothesize that an ancestral Cryptococcus strain gained the ability to sexually reproduce in pigeon guano and then swept the globe. PMID:17449657

Molecular epidemiology reveals genetic diversity among 363 isolates of the Cryptococcus neoformans and Cryptococcus gattii species complex in 61 Ivorian HIV-positive patients.

PubMed

Kassi, Fulgence K; Drakulovski, Pascal; Bellet, Virginie; Krasteva, Donika; Gatchitch, François; Doumbia, Adama; Kouakou, Gisèle A; Delaporte, Eric; Reynes, Jacques; Mallié, Michèle; Menan, Hervé I E; Bertout, Sebastien

2016-12-01

Cryptococcal meningitis is a severe opportunistic infection in HIV-infected patients. In Ivory Coast, despite the availability of antiretroviral treatment (ART), this infection is still prevalent. The study investigates the genetic diversity of 363 clinical isolates of Cryptococcus from 61 Ivorian HIV-positive patients, the occurrence of mixed infections and the in vitro antifungal susceptibility of the isolates. Serotyping was performed via LAC1 and CAP64 gene amplification. Genotyping was performed using the phage M13 core (GACA) 4 and (GTG) 5 primers and restriction fragment length polymorphism analysis of the URA5 gene. By PCR fingerprinting, the presence of the three serotypes were demonstrated among the 363 isolates in the population studied: A (n=318; 87.6%), AD (n=40; 11%) and B (n=4; 1.1%). Using PCR fingerprinting with primers M13 (GACA) 4 and (GTG) 5 , we grouped the isolates into 56 molecular subtypes. We observed a high frequency (39.3%) of mixed infections, with up to two different genotypes per sample. None of the isolates were resistant to amphotericin B. Only 0.3% and 1.1% of the isolates were resistant to fluconazole and flucytosine respectively. This study revealed the high genetic diversity among Cryptococcus isolates, the occurrence of mixed infections and a high antifungal susceptibility for the majority of Ivorian cryptococcal isolates. © 2016 Blackwell Verlag GmbH.

Cryptococcal transmigration across a model brain blood-barrier: evidence of the Trojan horse mechanism and differences between Cryptococcus neoformans var. grubii strain H99 and Cryptococcus gattii strain R265.

PubMed

Sorrell, Tania C; Juillard, Pierre-Georges; Djordjevic, Julianne T; Kaufman-Francis, Keren; Dietmann, Anelia; Milonig, Alban; Combes, Valery; Grau, Georges E R

2016-01-01

Cryptococcus neoformans (Cn) and Cryptococcus gattii (Cg) cause neurological disease and cross the BBB as free cells or in mononuclear phagocytes via the Trojan horse mechanism, although evidence for the latter is indirect. There is emerging evidence that Cn and the North American outbreak Cg strain (R265) more commonly cause neurological and lung disease, respectively. We have employed a widely validated in vitro model of the BBB, which utilizes the hCMEC/D3 cell line derived from human brain endothelial cells (HBEC) and the human macrophage-like cell line, THP-1, to investigate whether transport of dual fluorescence-labelled Cn and Cg across the BBB occurs within macrophages. We showed that phagocytosis of Cn by non-interferon (IFN)-γ stimulated THP-1 cells was higher than that of Cg. Although Cn and Cg-loaded THP-1 bound similarly to TNF-activated HBECs under shear stress, more Cn-loaded macrophages were transported across an intact HBEC monolayer, consistent with the predilection of Cn for CNS infection. Furthermore, Cn exhibited a higher rate of expulsion from transmigrated THP-1 compared with Cg. Our results therefore provide further evidence for transmigration of both Cn and Cg via the Trojan horse mechanism and a potential explanation for the predilection of Cn to cause CNS infection. Copyright © 2015 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.

Molecular diagnosis of cryptococcal meningitis in cerebrospinal fluid: comparison of primer sets for Cryptococcus neoformans and Cryptococcus gattii species complex.

PubMed

Martins, Marilena dos Anjos; Brighente, Kate Bastos Santos; Matos, Terezinha Aparecida de; Vidal, Jose Ernesto; Hipólito, Daise Damaris Carnietto de; Pereira-Chioccola, Vera Lucia

2015-01-01

This study evaluated the use of polymerase chain reaction for cryptococcal meningitis diagnosis in clinical samples. The sensitivity and specificity of the methodology were evaluated using eight Cryptococcus neoformans/C. gattii species complex reference strains and 165 cerebrospinal fluid samples from patients with neurological diseases divided into two groups: 96 patients with cryptococcal meningitis and AIDS; and 69 patients with other neurological opportunistic diseases (CRL/AIDS). Two primer sets were tested (CN4-CN5 and the multiplex CNa70S-CNa70A/CNb49S-CNb-49A that amplify a specific product for C. neoformans and another for C. gattii). CN4-CN5 primer set was positive in all Cryptococcus standard strains and in 94.8% in DNA samples from cryptococcal meningitis and AIDS group. With the multiplex, no 448-bp product of C. gattii was observed in the clinical samples of either group. The 695bp products of C. neoformans were observed only in 64.6% of the cryptococcal meningitis and AIDS group. This primer set was negative for two standard strains. The specificity based on the negative samples from the CTL/AIDS group was 98.5% in both primer sets. These data suggest that the CN4/CN5 primer set was highly sensitive for the identification of C. neoformans/C. gattii species complex in cerebrospinal fluid samples from patients with clinical suspicion of cryptococcal meningitis. Copyright © 2014 Elsevier Editora Ltda. All rights reserved.

Uncommon opportunistic fungal infections of oral cavity: A review

PubMed Central

Deepa, AG; Nair, Bindu J; Sivakumar, TT; Joseph, Anna P

2014-01-01

The majority of opportunistic oral mucosal fungal infections are due to Candida albicans and Aspergillus fumigatus species. Mucor and Cryptococcus also have a major role in causing oral infections, whereas Geotrichum, Fusarium, Rhodotorula, Saccharomyces and Penicillium marneffei are uncommon pathogens in the oral cavity. The broad spectrum of clinical presentation includes pseudo-membranes, abscesses, ulcers, pustules and extensive tissue necrosis involving bone. This review discusses various uncommon opportunistic fungal infections affecting the oral cavity including their morphology, clinical features and diagnostic methods. PMID:25328305

Conversion of beet molasses and cheese whey into fatty acid methyl esters by the yeast Cryptococcus curvatus.

PubMed

Takakuwa, Naoya; Saito, Katsuichi

2010-01-01

Eighty-one yeast isolates from raw milk were surveyed for the production of fatty acid methyl esters (FAME). Only one species, identified as Cryptococcus curvatus, produced FAME at a detectable level. Cr. curvatus TYC-19 produced more FAME from beet molasses and cheese whey medium than other strains of the same species. In both media, the major FAME produced were linoleic and oleic acid methyl esters. Sequence analysis of the internal transcribed spacer region of ribosomal DNA indicated that TYC-19 diverged from the same species.

Genome sequence of a microbial lipid producing fungus Cryptococcus albidus NT2002.

PubMed

Yong, Xiaoyu; Yan, Zhiying; Xu, Lin; Zhou, Jun; Wu, Xiayuan; Wu, Yuandong; Li, Yang; Chen, Zugeng; Zhou, Hua; Wei, Ping; Jia, Honghua

2016-04-10

Cryptococcus albidus NT2002, isolated from the soil in Xinjiang, China, appeared to have the ability to accumulate microbial lipid by utilizing various carbon sources. The predominant properties make it as a potential bio-platform for biodiesel production. Here, we report the complete genome sequence of C. albidus NT2002, which might provide a basis for further elucidation of the genetic background of this promising strain for developing metabolic engineering strategies to produce biodiesel in a green and sustainable manner. Copyright © 2016 Elsevier B.V. All rights reserved.

Yeast species associated with wine grapes in China.

PubMed

Li, Shuang-Shi; Cheng, Chao; Li, Zheng; Chen, Jing-Yu; Yan, Bin; Han, Bei-Zhong; Reeves, Malcolm

2010-03-31

Having more information on the yeast ecology of grapes is important for wine-makers to produce wine with high quality and typical attributes. China is a significant wine-consuming country and is becoming a serious wine-producer, but little has been reported about the yeast ecology of local ecosystems. This study provides the first step towards the exploitation of the yeast wealth in China's vine-growing regions. The aim of this study was to investigate the yeast population density and diversity on three grape varieties cultivated in four representative vine-growing regions of China. Yeast species diversity was evaluated by using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and sequence analysis of the 5.8S internal transcribed spacer (ITS) ribosomal DNA (rDNA) region of cultivable yeasts. The grapes harbored yeast populations at 10(2)-10(6)CFU/mL, consisting mostly of non-Saccharomyces species. Seventeen different yeast species belonging to eight genera were detected on the grape samples tested, including Hanseniaspora uvarum, Cryptococcus flavescens, Pichia fermentans, Candida zemplinina, Cryptococcus carnescens, Candida inconpicua, Zygosaccharomyces fermentati, Issatchenkia terricola, Candida quercitrusa, Hanseniaspora guilliermondii, Candida bombi, Zygosaccharomyces bailii, Sporidiobolus pararoseus, Cryptococcus magnus, Metschnikowia pulcherrima, Issatchenkia orientalis and Pichia guilliermondii. H. uvarum and C. flavescens were the dominant species present on the grapes. For the first time Sporidiobolus pararoseus was discovered as an inhabitant of the grape ecosystem. The yeast community on grape berries was influenced by the grape chemical composition, vine-variety and vine-growing region. This study is the first to identify the yeast communities associated with grapes in China using molecular methods. The results enrich our knowledge of wine-related microorganisms, and can be used to promote the development of the local wine industry. Copyright 2010 Elsevier B.V. All rights reserved.

Genome sequences of three phytopathogenic species of the Magnaporthaceae family of fungi

USDA-ARS?s Scientific Manuscript database

Magnaporthaceae is a family of ascomycetes that includes three fungi of great economic importance: Magnaporthe oryzae, Gaeumannomyces graminis var. tritici, and Magnaporthe poae. These three fungi cause widespread disease and loss in cereal and grass crops, including rice blast disease (M. oryzae), ...

The microbial ecology of wine grape berries.

PubMed

Barata, A; Malfeito-Ferreira, M; Loureiro, V

2012-02-15

Grapes have a complex microbial ecology including filamentous fungi, yeasts and bacteria with different physiological characteristics and effects upon wine production. Some species are only found in grapes, such as parasitic fungi and environmental bacteria, while others have the ability to survive and grow in wines, constituting the wine microbial consortium. This consortium covers yeast species, lactic acid bacteria and acetic acid bacteria. The proportion of these microorganisms depends on the grape ripening stage and on the availability of nutrients. Grape berries are susceptible to fungal parasites until véraison after which the microbiota of truly intact berries is similar to that of plant leaves, which is dominated by basidiomycetous yeasts (e.g. Cryptococcus spp., Rhodotorula spp. Sporobolomyces spp.) and the yeast-like fungus Aureobasidium pullulans. The cuticle of visually intact berries may bear microfissures and softens with ripening, increasing nutrient availability and explaining the possible dominance by the oxidative or weakly fermentative ascomycetous populations (e.g. Candida spp., Hanseniaspora spp., Metschnikowia spp., Pichia spp.) approaching harvest time. When grape skin is clearly damaged, the availability of high sugar concentrations on the berry surface favours the increase of ascomycetes with higher fermentative activity like Pichia spp. and Zygoascus hellenicus, including dangerous wine spoilage yeasts (e.g. Zygosaccharomyces spp., Torulaspora spp.), and of acetic acid bacteria (e.g. Gluconobacter spp., Acetobacter spp.). The sugar fermenting species Saccharomyces cerevisiae is rarely found on unblemished berries, being favoured by grape damage. Lactic acid bacteria are minor partners of grape microbiota and while being the typical agent of malolactic fermentation, Oenococcus oeni has been seldom isolated from grapes in the vineyard. Environmental ubiquitous bacteria of the genus Enterobacter spp., Enterococcus spp., Bacillus spp., Burkholderia spp., Serratia spp., Staphylococcus spp., among others, have been isolated from grapes but do not have the ability to grow in wines. Saprophytic moulds, like Botrytis cinerea, causing grey rot, or Aspergillus spp., possibly producing ochratoxin, are only active in the vineyard, although their metabolites may affect wine quality during grape processing. The impact of damaged grapes in yeast ecology has been underestimated mostly because of inaccurate grape sampling. Injured berries hidden in apparently sound bunches explain the recovery of a higher number of species when whole bunches are picked. Grape health status is the main factor affecting the microbial ecology of grapes, increasing both microbial numbers and species diversity. Therefore, the influence of abiotic (e.g. climate, rain, hail), biotic (e.g. insects, birds, phytopathogenic and saprophytic moulds) and viticultural (e.g. fungicides) factors is dependent on their primary damaging effect. Copyright © 2011 Elsevier B.V. All rights reserved.

Antifungal susceptibility of clinical and environmental isolates of Cryptococcus neoformans to four antifungal drugs determined by two techniques.

PubMed

Moraes, E M P; Prímola, N S; Hamdan, Júnia Soares

2003-06-01

A total of 64 Cryptococcus neoformans strains, including clinical and environmental Brazilian isolates var. neoformans and var. gattii, were tested for susceptibility to amphotericin B, 5-flucytosine, fluconazole and itraconazole. The tests were performed according to the recommendations of National Committee of Clinical Laboratory Standards and the method of macrodilution in liquid medium of Shadomy et al. [Manual de Microbiologia Clínica, 4th ed. Buenos Aires: Editorial Medica Panamericana, 1987: 1229-38]. For most drugs there was a significant difference between the readings taken at 24 and 48 h with both methods. When the minimum inhibitory concentrations obtained by the two techniques were compared, significant differences were observed for amphotericin B and fluconazole. Overall, differences in drug susceptibility with respect to the origin of the isolates or the variety of the fungus were not observed. As an exception, the gattii variety exhibited a high resistance rate to amphotericin B when the technique of Shadomy et al. was applied, a fact possibly related to the greater difficulty for treatment of the disease caused by this fungal variety.

Cryptococcosis outbreak in psittacine birds in Brazil.

PubMed

Raso, T F; Werther, K; Miranda, E T; Mendes-Giannini, M J S

2004-08-01

An outbreak of cryptococcosis occurred in a breeding aviary in São Paulo, Brazil. Seven psittacine birds (of species Charmosyna papou, Lorius lory, Trichoglossus goldiei, Psittacula krameri and Psittacus erithacus) died of disseminated cryptococcosis. Incoordination, progressive paralysis and difficulty in flying were seen in five birds, whereas superficial lesions coincident with respiratory alterations were seen in two birds. Encapsulated yeasts suggestive of Cryptococcus sp. were seen in faecal smears stained with India ink in two cases. Histological examination of the birds showed cryptococcal cells in various tissues, including the beak, choana, sinus, lungs, air sacs, heart, liver, spleen, kidneys, intestines and central nervous system. High titres of cryptococcal antigen were observed in the serum of an affected bird. In this case, titres increased during treatment and the bird eventually died. Yeasts were isolated from the nasal mass, faeces and liver of one bird. Cryptococcus neoformans var. gattii serovar B was identified based on biochemical, physiological and serological tests. These strains were resistant (minimum inhibitory concentration 64 microg/ml) to fluconazole. This is the first report of C. neoformans var. gattii occurring in psittacine birds in Brazil.

EDTA Inhibits Biofilm Formation, Extracellular Vesicular Secretion, and Shedding of the Capsular Polysaccharide Glucuronoxylomannan by Cryptococcus neoformans

PubMed Central

Robertson, Emma J.; Wolf, Julie M.

2012-01-01

The fungal pathogen Cryptococcus neoformans can grow as a biofilm on a range of synthetic and prosthetic materials. Cryptococcal biofilm formation can complicate the placement of shunts used to relieve increased intracranial pressure in cryptococcal meningitis and can serve as a nidus for chronic infection. Biofilms are generally advantageous to pathogens in vivo, as they can confer resistance to antimicrobial compounds, including fluconazole and voriconazole in the case of C. neoformans. EDTA can inhibit biofilm formation by several microbes and enhances the susceptibility of biofilms to antifungal drugs. In this study, we evaluated the effect of sublethal concentrations of EDTA on the growth of cryptococcal biofilms. EDTA inhibited biofilm growth by C. neoformans, and the inhibition could be reversed by the addition of magnesium or calcium, implying that the inhibitory effect was by divalent cation starvation. EDTA also reduced the amount of the capsular polysaccharide glucuronoxylomannan shed into the biofilm matrix and decreased vesicular secretion from the cell, thus providing a potential mechanism for the inhibitory effect of this cation-chelating compound. Our data imply that the growth of C. neoformans biofilms requires the presence of divalent metals in the growth medium and suggest that cations are required for the export of materials needed for biofilm formation, possibly including extracellular vesicles. PMID:22941091

Noncanoncial signal recognition particle RNAs in a major eukaryotic phylum revealed by purification of SRP from the human pathogen Cryptococcus neoformans

PubMed Central

Dumesic, Phillip A.; Rosenblad, Magnus A.; Samuelsson, Tore; Nguyen, Tiffany; Moresco, James J.; Yates, John R.; Madhani, Hiten D.

2015-01-01

Despite conservation of the signal recognition particle (SRP) from bacteria to man, computational approaches have failed to identify SRP components from genomes of many lower eukaryotes, raising the possibility that they have been lost or altered in those lineages. We report purification and analysis of SRP in the human pathogen Cryptococcus neoformans, providing the first description of SRP in basidiomycetous yeast. The C. neoformans SRP RNA displays a predicted structure in which the universally conserved helix 8 contains an unprecedented stem-loop insertion. Guided by this sequence, we computationally identified 152 SRP RNAs throughout the phylum Basidiomycota. This analysis revealed additional helix 8 alterations including single and double stem-loop insertions as well as loop diminutions affecting RNA structural elements that are otherwise conserved from bacteria to man. Strikingly, these SRP RNA features in Basidiomycota are accompanied by phylum-specific alterations in the RNA-binding domain of Srp54, the SRP protein subunit that directly interacts with helix 8. Our findings reveal unexpected fungal SRP diversity and suggest coevolution of the two most conserved SRP features—SRP RNA helix 8 and Srp54—in basidiomycetes. Because members of this phylum include important human and plant pathogens, these noncanonical features provide new targets for antifungal compound development. PMID:26275773

Carbon source utilization and inhibitor tolerance of 45 oleaginous yeast species

PubMed Central

Sitepu, Irnayuli; Selby, Tylan; Lin, Ting; Zhu, Shirley; Boundy-Mills, Kyria

2014-01-01

Conversion of lignocellulosic hydrolysates to lipids using oleaginous (high lipid) yeasts requires alignment of the hydrolysate composition with the characteristics of the yeast strain, including ability to utilize certain nutrients, ability to grow independently of costly nutrients such as vitamins, and ability to tolerate inhibitors. Some combination of these characteristics may be present in wild strains. In this study, 48 oleaginous yeast strains belonging to 45 species were tested for ability to utilize carbon sources associated with lignocellulosic hydrolysates, tolerate inhibitors, and grow in medium without supplemented vitamins. Some well-studied oleaginous yeast species, as well as some that have not been frequently utilized in research or industrial production, emerged as promising candidates for industrial use due to ability to utilize many carbon sources, including Cryptococcus aureus, Cryptococcus laurentii, Hanaella aff. zeae, Tremella encephala, and Trichosporon coremiiforme. Other species excelled in inhibitor tolerance, including Candida aff. tropicalis, Cyberlindnera jadinii, Metschnikowia pulcherrima Schwanniomyces occidentalis and Wickerhamomyces ciferii. No yeast tested could utilize all carbon sources and tolerate all inhibitors tested. These results indicate that yeast strains should be selected based on characteristics compatible with the composition of the targeted hydrolysate. Other factors to consider include the production of valuable co-products such as carotenoids, availability of genetic tools, biosafety level, and flocculation of the yeast strain. The data generated in this study will aid in aligning yeasts with compatible hydrolysates for conversion of carbohydrates to lipids to be used for biofuels and other oleochemicals. PMID:24818698

Yeast: An Overlooked Component of Bactrocera tryoni (Diptera: Tephritidae) Larval Gut Microbiota.

PubMed

Deutscher, Ania T; Reynolds, Olivia L; Chapman, Toni A

2017-02-01

Yeasts, often in hydrolyzed form, are key ingredients in the larval and adult diets of tephritid fruit fly colonies. However, very little is known about the presence or role of yeasts in the diets of tephritid fruit flies in nature. Previous studies have identified bacteria but not detected yeasts in the gut of Queensland fruit fly, Bactrocera tryoni (Froggatt), one of Australia's most economically damaging insect pests of horticultural crops and of significant biosecurity concern domestically and internationally. Here we demonstrate that cultivable yeasts are commonly found in the gut of B. tryoni larvae from fruit hosts. Analysis of the ITS1, 5.8S rRNA gene, and ITS2 sequences of randomly selected isolates identified yeasts and yeast-like fungi of the genera Aureobasidium, Candida, Cryptococcus, Hanseniaspora, Pichia, and Starmerella. The prevalence of these yeasts in fruits suggests that larvae consume the yeasts as part of their diet. This work highlights that yeasts should be considered in future tephritid larval gut microbiota studies. Understanding tephritid-microbial symbiont interactions will lead to improvements in artificial diets and the quality of mass-reared tephritids for the sterile insect technique. © The Authors 2016. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Correlation of maple sap composition with bacterial and fungal communities determined by multiplex automated ribosomal intergenic spacer analysis (MARISA).

PubMed

Filteau, Marie; Lagacé, Luc; LaPointe, Gisèle; Roy, Denis

2011-08-01

During collection, maple sap is contaminated by bacteria and fungi that subsequently colonize the tubing system. The bacterial microbiota has been more characterized than the fungal microbiota, but the impact of both components on maple sap quality remains unclear. This study focused on identifying bacterial and fungal members of maple sap and correlating microbiota composition with maple sap properties. A multiplex automated ribosomal intergenic spacer analysis (MARISA) method was developed to presumptively identify bacterial and fungal members of maple sap samples collected from 19 production sites during the tapping period. Results indicate that the fungal community of maple sap is mainly composed of yeast related to Mrakia sp., Mrakiella sp., Guehomyces pullulans, Cryptococcus victoriae and Williopsis saturnus. Mrakia, Mrakiella and Guehomyces peaks were identified in samples of all production sites and can be considered dominant and stable members of the fungal microbiota of maple sap. A multivariate analysis based on MARISA profiles and maple sap chemical composition data showed correlations between Candida sake, Janthinobacterium lividum, Williopsis sp., Leuconostoc mesenteroides, Mrakia sp., Rhodococcus sp., Pseudomonas tolaasii, G. pullulans and maple sap composition at different flow periods. This study provides new insights on the relationship between microbial community and maple sap quality. Copyright © 2011 Elsevier Ltd. All rights reserved.

Ebselen exerts antifungal activity by regulating glutathione (GSH) and reactive oxygen species (ROS) production in fungal cells.

PubMed

Thangamani, Shankar; Eldesouky, Hassan E; Mohammad, Haroon; Pascuzzi, Pete E; Avramova, Larisa; Hazbun, Tony R; Seleem, Mohamed N

2017-01-01

Ebselen, an organoselenium compound and a clinically safe molecule has been reported to possess potent antifungal activity, but its antifungal mechanism of action and in vivo antifungal activity remain unclear. The antifungal effect of ebselen was tested against Candida albicans, C. glabrata, C. tropicalis, C. parapsilosis, Cryptococcus neoformans, and C. gattii clinical isolates. Chemogenomic profiling and biochemical assays were employed to identify the antifungal target of ebselen. Ebselen's antifungal activity in vivo was investigated in a Caenorhabditis elegans animal model. Ebselen exhibits potent antifungal activity against both Candida spp. and Cryptococcus spp., at concentrations ranging from 0.5 to 2μg/ml. Ebselen rapidly eradicates a high fungal inoculum within 2h of treatment. Investigation of the drug's antifungal mechanism of action indicates that ebselen depletes intracellular glutathione (GSH) levels, leading to increased production of reactive oxygen species (ROS), and thereby disturbs the redox homeostasis in fungal cells. Examination of ebselen's in vivo antifungal activity in two Caenorhabditis elegans models of infection demonstrate that ebselen is superior to conventional antifungal drugs (fluconazole, flucytosine and amphotericin) in reducing Candida and Cryptococcus fungal load. Ebselen possesses potent antifungal activity against clinically relevant isolates of both Candida and Cryptococcus by regulating GSH and ROS production. The potent in vivo antifungal activity of ebselen supports further investigation for repurposing it for use as an antifungal agent. The present study shows that ebselen targets glutathione and also support that glutathione as a potential target for antifungal drug development. Copyright © 2016 Elsevier B.V. All rights reserved.

Taxonomic characterization, adaptation strategies and biotechnological potential of cryophilic yeasts from ice cores of Midre Lovénbreen glacier, Svalbard, Arctic.

PubMed

Singh, Purnima; Tsuji, Masaharu; Singh, Shiv Mohan; Roy, Utpal; Hoshino, Tamotsu

2013-04-01

Ten strains of cryophilic yeast were studied from glacier ice cores of Svalbard, Arctic. The ice melt samples contained about 3×10(3) - 1×10(4) colony forming unit (CFUs) per ml. Sequence analysis of the isolates, using D1/D2 domain identified five species of yeasts: Cryptococcus adeliensis (MLB-18 JX192655), Cryptococcus albidosimilis (MLB-19 JX192656), Cryptococcus saitoi (MLB-22 JX192659), Rhodosporidium lusitaniae (MLB-20 JX192657), and Rhodotorula mucilaginosa (MLB-27 JX192664). Effect of temperature on growth of these isolates was studied. The strains are able to grow at temperatures ranging between 1 and 20°C. Screening of the cultures for amylase, cellulase, protease, lipase, urease and catalase activity were carried out indicating varying amounts of enzyme production at different temperatures. Characterization of lipase in strain Cryptococcus sp. MLB-24 was performed. Fatty acid methyl ester (FAME) analysis of the cultures grown at four different temperatures (1, 4, 15, and 20°C) was also done. Decrease in temperature was reported to cause increase in concentration of unsaturated fatty acids. High amount of oleic acid accumulated with increase in temperature. These fatty acids possibly help the strains to survive in glacial ice core cold environment. The extracellular and intracellular filtrate of the cultures showed negative antifreeze protein (AFP) activity. The observations indicate that probably the isolates in the present undertaking adapt to low temperatures, by enzyme and PUFA secretion rather than by antifreeze protein secretion. Copyright © 2013 Elsevier Inc. All rights reserved.

Environmental sampling of Ceratonia siliqua (carob) trees in Spain reveals the presence of the rare Cryptococcus gattii genotype AFLP7/VGIV.

PubMed

Linares, Carlos; Colom, María Francisca; Torreblanca, Marina; Esteban, Violeta; Romera, Álvaro; Hagen, Ferry

2015-01-01

Cryptococcus gattii is a pathogenic basidiomycetous yeast that is emerging in temperate climate zones worldwide. C. gattii has repetitively been isolated from numerous tree species. Ongoing environmental sampling and molecular characterization is essential to understand the presence of this primary pathogenic microorganism in the Mediterranean environment. To report the first isolation of the rare C. gattii genotype AFLP7/VGIV from the environment in Europe. Samples were collected from woody debris of carob trees (Ceratonia siliqua) and olive trees (Olea europaea) in El Perelló, Tarragona, Spain. Cryptococcus species were further characterized by using URA5-RFLP, MALDI-TOF, AFLP and MLST. The antifungal susceptibility profile to amphotericin B, 5-fluorocytosine, fluconazole, itraconazole, posaconazole and voriconazole was determined using Sensititre Yeast One and E-test. Cultures from one carob tree revealed the presence of ten Cryptococcus-like colonies. One colony was identified as C. gattii, and subsequent molecular characterization showed that it was an α mating-type that belonged to the rare genotype AFLP7/VGIV. Antifungal susceptibility testing showed values within the range of sensitivity described for other isolates of the same genotype and within the epidemiological cutoff values for this species. The isolation of the rare C. gattii genotype AFLP7/VGIV in Spain is the first report in the European environment, implying the possible presence in other regions of the Mediterranean area, and underlines that clinicians must be aware for C. gattii infections in healthy individuals. Copyright © 2014 Revista Iberoamericana de Micología. Published by Elsevier Espana. All rights reserved.

Cryptococcus neoformans capsule protects cell from oxygen reactive species generated by antimicrobial photodynamic inactivation

NASA Astrophysics Data System (ADS)

Prates, Renato Araujo; Hamblin, Michael R.; Kato, Ilka T.; Fuchs, Beth; Mylonakis, Eleytherios; Simões Ribeiro, Martha; Tegos, George

2011-03-01

Antimicrobial photodynamic inactivation (APDI) is based on the utilization of substances that can photosensitize biological tissues and are capable of being activated in the presence of light. Cryptococcus neoformans is an yeast surrounded by a capsule composed primarily of glucoronoxylomannan that plays an important role in its virulence. This yeast causes infection on skin, lungs and brain that can be associated with neurological sequelae and neurosurgical interventions, and its conventional treatment requires prolonged antifungal therapy, which presents important adverse effects. The aim of this study was to evaluate the protective effect of Cryptococcus neoformans capsule against reactive oxygen species generated by APDI. Cryptococcus neoformans KN99α, which is a strain able to produce capsule, and CAP59 that does not present capsule production were submitted to APDI using methylene blue (MB), rose bengal (RB), and pL-ce6 as photosensitizers (PS). Then microbial inactivation was evaluated by counting colony form units following APDI and confocal laser scanning microscopy (CLSM) illustrated localization as well as the preferential accumulation of PS into the fungal cells. C. neoformans KN99α was more resistant to APDI than CAP59 for all PSs tested. CLSM showed incorporation of MB and RB into the cytoplasm and a preferential uptake in mitochondria. A nuclear accumulation of MB was also observed. Contrarily, pL-ce6 appears accumulated in cell wall and cell membrane and minimal florescence was observed inside the fungal cells. In conclusion, the ability of C. neoformans to form capsule enhances survival following APDI.

Potential Antiviral Agents from Marine Fungi: An Overview

PubMed Central

Zorofchian Moghadamtousi, Soheil; Nikzad, Sonia; Abdul Kadir, Habsah; Abubakar, Sazaly; Zandi, Keivan

2015-01-01

Biodiversity of the marine world is only partially subjected to detailed scientific scrutiny in comparison to terrestrial life. Life in the marine world depends heavily on marine fungi scavenging the oceans of lifeless plants and animals and entering them into the nutrient cycle by. Approximately 150 to 200 new compounds, including alkaloids, sesquiterpenes, polyketides, and aromatic compounds, are identified from marine fungi annually. In recent years, numerous investigations demonstrated the tremendous potential of marine fungi as a promising source to develop new antivirals against different important viruses, including herpes simplex viruses, the human immunodeficiency virus, and the influenza virus. Various genera of marine fungi such as Aspergillus, Penicillium, Cladosporium, and Fusarium were subjected to compound isolation and antiviral studies, which led to an illustration of the strong antiviral activity of a variety of marine fungi-derived compounds. The present review strives to summarize all available knowledge on active compounds isolated from marine fungi with antiviral activity. PMID:26204947

Abdominal cryptococcosis in two dogs: diagnosis and medical management.

PubMed

Tangeman, Lindsay; Davignon, Danielle; Patel, Reema; Littman, Meryl

2015-01-01

Canine cryptococcosis cases are typically reported as neurologic, disseminated, or both. There have been few reports of other parenchymal organ involvement. Dogs infected with Cryptococcus spp. are likely to develop central nervous system involvement, and those that are severely affected are treated aggressively with surgery and/or amphotericin B. This report describes two cases of canine abdominal cryptococcosis: one boxer with primary alimentary cryptococcosis alone and one miniature schnauzer with pancreatic and disseminated cryptococcosis. The boxer is unique in that the dog suffered from primary alimentary cryptococcosis without dissemination, secondary anemia due to gastrointestinal losses, and is the second case to have Cryptococcus spp. identified on fecal examination as part of the diagnostic workup. Unlike previous reports, surgery was not performed in either case, and both dogs were treated with fluconazole alone. Currently, both dogs are free from clinical signs, and Cryptococcus spp. antigen titers are negative at 17 and 15 mo after initial presentation. These cases suggest fluconazole may be effective therapy alone for canine abdominal cryptococcosis, negating the need for high-risk therapy options such as surgery and/or amphotericin B in some cases.

A Disseminated Cryptococcus gattii VGIIa Infection in a Citron-Crested Cockatoo (Cacatua sulphurea citrinocristata) in Québec, Canada.

PubMed

Maccolini, Édouard O; Dufresne, Philippe J; Aschenbroich, Sophie Ann; McHale, Brittany; Fairbrother, Julie-Hélène; Bédard, Christian; Hébert, Julie A

2017-06-01

Cryptococcus gattii infection in mammals and birds has been confined historically to tropical and subtropical regions in Australia, Southeast Asia, Africa, and South America. Since the early 2000s, numerous reports describe the emergence of C. gattii on the Pacific Coast of North America. We report on a C. gattii infection in an 8-year-old male citron-crested cockatoo (Cacatua sulphurea citrinocristata) hatched on the Canadian Pacific Coast and raised in the province of Québec, Canada. The bird developed a slow growing ulcerated, fleshy, crusty, and hemorrhagic mass infiltrating the left lower rhamphotheca. Cryptococcus gattii infection was confirmed by cytologic examination of a fine needle aspirate of the mass, and results of fungal culture and sequencing. The genotype of the strain was determined to be VGIIa sequence type 20, the strongly overrepresented subgroup found on the Canadian Pacific coast. Minimum inhibitory concentrations for multiple antifungal drugs were determined. The bird received fluconazole but died acutely 55 days after initial presentation. Postmortem examination revealed a disseminated infection, with involvement of the beak, lungs, spleen, and brain.

Molecular characterization of environmental Cryptococcus neoformans VNII isolates in Jos, Plateau State, Nigeria.

PubMed

Nnadi, N E; Enweani, I B; Cogliati, M; Ayanbimpe, G M; Okolo, M O; Kim, E; Sabitu, M Z; Criseo, G; Romeo, O; Scordino, F

2016-12-01

Cryptococcus neoformans and Cryptococcus gattii are encapsulated yeasts able to cause fatal neurological infections in both human and other mammals. Cryptococcosis is the most common fungal infection of the central nervous system and has a huge burden in sub-Saharan Africa and South East Asia. Bird excreta are considered an environmental reservoir for C. neoformans in urban areas, therefore a study aimed at isolating and characterizing this yeast is important in disease management. In this study, one hundred samples of pigeon droppings were collected in Jos, Plateau State, Nigeria. C. neoformans was isolated from three samples and initially identified using standard phenotypic and biochemical tests. Molecular analysis revealed that all three isolates belonged to C. neoformans genotype VNII, mating type α and were assigned to the sequence type ST43 by multilocus sequence typing analysis. This study reports, for the first time, the molecular characterization of C. neoformans in Nigeria, where little is still known about the environmental distribution of the genotypes, serotypes and mating types of this important human pathogen. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

Importance of Resolving Fungal Nomenclature: the Case of Multiple Pathogenic Species in the Cryptococcus Genus

PubMed Central

Lumbsch, H. Thorsten; Bertout, Sebastien; Cabañes, F. Javier; Carbia, Mauricio; Chen, Min; Cuétara, Maria S.; Espinel-Ingroff, Ana; Falk, Rama; Ferrer Rodríguez, Consuelo; Fraser, James A.; Khan, Ziauddin; Kurtzman, Cletus P.; Lagrou, Katrien; Liao, Wanqing; Linares, Carlos; Nielsen, Kirsten; Pan, Weihua; Pekmezovic, Marina; Romeo, Orazio; Sánchez, Manuel; Sampaio, Ana; Sriburee, Pojana; Sugita, Takashi; Takashima, Masako; Taylor, John W.; Theelen, Bart; Tomazin, Rok; Verweij, Paul E.; Wahyuningsih, Retno

2017-01-01

ABSTRACT Cryptococcosis is a major fungal disease caused by members of the Cryptococcus gattii and Cryptococcus neoformans species complexes. After more than 15 years of molecular genetic and phenotypic studies and much debate, a proposal for a taxonomic revision was made. The two varieties within C. neoformans were raised to species level, and the same was done for five genotypes within C. gattii. In a recent perspective (K. J. Kwon-Chung et al., mSphere 2:e00357-16, 2017, https://doi.org/10.1128/mSphere.00357-16), it was argued that this taxonomic proposal was premature and without consensus in the community. Although the authors of the perspective recognized the existence of genetic diversity, they preferred the use of the informal nomenclature “C. neoformans species complex” and “C. gattii species complex.” Here we highlight the advantage of recognizing these seven species, as ignoring these species will impede deciphering further biologically and clinically relevant differences between them, which may in turn delay future clinical advances. PMID:28875175

Enhanced itaconic acid production in Aspergillus with increased LaeA expression

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dai, Ziyu; Baker, Scott E.

Fungi, such as Aspergillus niger, having a dolichyl-P-Man:Man(5)GlcNAc(2)-PP-dolichyl mannosyltransferase (Alg3) gene genetic inactivation, increased expression of a loss of aflR expression A (LaeA), or both, are described. In some examples, such mutants have several phenotypes, including an increased production of citric acid relative to the parental strain. Methods of using the disclosed fungi to make citric acid are also described, as are compositions and kits including the disclosed fungi. Further described are Aspergillus terreus fungi overexpressing the LaeA gene and the use of such fungi for the production of itaconic acid.

Some Strychnos spinosa (Loganiaceae) leaf extracts and fractions have good antimicrobial activities and low cytotoxicities.

PubMed

Isa, Adamu Imam; Awouafack, Maurice Ducret; Dzoyem, Jean Paul; Aliyu, Mohammed; Magaji, Rabiu AbduSsalam; Ayo, Joseph Olusegun; Eloff, Jacobus Nicolaas

2014-11-27

Strychnos spinosa Lam. is a deciduous tree used in traditional medicine to treat infectious diseases. This study is designed to determine the antimicrobial, antioxidant and cytotoxic activities of extracts and fractions from leaves of S. spinosa. Extracts were obtained by maceration with acetone, methanol and dichloromethane/methanol (1/1) while fractions were prepared by liquid-liquid fractionation of the acetone extract. A broth serial microdilution method with tetrazolium violet as growth indicator was used to determine the minimum inhibitory concentration (MIC) against fungi, Gram-positive and Gram-negative bacteria. The antioxidant activity was determined using free-radical-scavenging assays, and the 3-(4,5-dimethylthiazolyl-2)-2,5-diphenyltetrazolium bromide reduction assay was used to determine cytotoxicity. Four extracts and five fractions had good to weak antimicrobial activity with MICs ranging from 0.04 to >1.25 mg/ml against both fungi and bacteria. The chloroform and ethyl acetate fractions had an MIC of 0.08 mg/ml against Aspergillus fumigatus. The n-butanol fraction had an MIC of 0.04 mg/ml against Cryptococcus neoformans. The hexane and chloroform fractions had an MIC of 0.08 mg/ml against Staphylococcus aureus. The antioxidant activities were much lower than that of the positive controls. Except for the alkaloid extract, all the extracts and fractions had free-radical-scavenging activity (IC50 ranging from 33.66 to 314.30 μg/ml). The cytotoxicity on Vero cells was reasonable to low with LC50 values ranging between 30.56 and 689.39 μg/ml. The acetone extract and the chloroform fraction had the highest antibacterial activity. By solvent-solvent fractionation it was possible to increase the activity against A. fumigatus and to decrease the cytotoxicity leading to a potentially useful product to protect animals against aspergillosis. Our results therefore support the use of S. spinosa leaves in traditional medicine to treat infectious diseases.

Cyclic dipeptides from rhabditid entomopathogenic nematode-associated Bacillus cereus have antimicrobial activities.

PubMed

Nishanth Kumar, S; Nath, Vishnu Sukumari; Pratap Chandran, R; Nambisan, Bala

2014-02-01

The cell free culture filtrate of Bacillus cereus associated with an entomopathogenic nematode, Rhabditis (Oscheius) sp. exhibited strong antimicrobial activity. The ethyl acetate extract of the bacterial culture filtrate was purified by silica gel column chromatography to obtain four bioactive compounds. The structure and absolute stereochemistry of these compounds were determined based on extensive spectroscopic analyses (FABMS, (1)H NMR, (13)C NMR, (1)H-(1)H COSY, (1)H-(13)C HMBC) and Marfey's method. The compounds were identified as cyclic dipeptides (CDPs): cyclo(L-Pro-L-Trp), cyclo(L-Leu-L-Val), cyclo(D-Pro-D-Met), and cyclo(D-Pro-D-Phe), respectively. Compounds recorded significant antibacterial activity against all the test bacteria (Staphylococcus epidermidis, Staphylococcus aureus, Klebsiella pneumoniae, Escherichia coli, Pseudomonas aeruginosa and methicillin-resistant S. aureus) except cyclo(L-Leu-L-Val). Cyclo(L-Leu-L-Val) recorded activity only against Gram positive bacteria. Best antibacterial activity was recorded by cyclo(L-Pro-L-Trp) against S. aureus (4 μg/ml). The four compounds were active against all the five fungi tested (Trichophyton rubrum, Aspergillus flavus, Candida albicans, Candida tropicalis and Cryptococcus neoformans) and the activity was compared with amphotericin B, the standard fungicide. The highest activity of 1 μg/ml by cyclo(L-Pro-L-Trp) was recorded against T. rubrum, a human pathogen responsible for causing athlete's foot, jock itch, and ringworm. The activity of cyclo(L-Pro-L-Trp) against T. rubrum, C. neoformans and C. albicans were better than amphotericin B, the standard antifungal agent. To our knowledge, this is the first report of antifungal activity of CDPs against the human pathogenic fungi T. rubrum and C. neoformans. The four CDPs are nontoxic to healthy human cell line up to 200 μg/ml. We conclude that the bacterium associated with entomopathogenic nematode is promising sources of natural antimicrobial secondary metabolites, which may receive greater benefit as potential sources of new drugs in the pharmaceutical industry.

Arylamine N-acetyltransferases in mycotoxigenic and related fungi of agricultural significance

USDA-ARS?s Scientific Manuscript database

Mycotoxigenic fungi are of worldwide concern, as they contaminate crops and compromise food safety. Many of these fungi are also aggressive plant pathogens with devastating effects on maize, and wheat. The host plants possess a variety of defensive mechanisms against those fungi, including the produ...

Cryptococcus neoformans Iron-Sulfur Protein Biogenesis Machinery Is a Novel Layer of Protection against Cu Stress.

PubMed

Garcia-Santamarina, Sarela; Uzarska, Marta A; Festa, Richard A; Lill, Roland; Thiele, Dennis J

2017-10-31

Copper (Cu) ions serve as catalytic cofactors to drive key biochemical processes, and yet Cu levels that exceed cellular homeostatic control capacity are toxic. The underlying mechanisms for Cu toxicity are poorly understood. During pulmonary infection by the fungal pathogen Cryptococcus neoformans , host alveolar macrophages compartmentalize Cu to the phagosome, and the ability to detoxify Cu is critical for its survival and virulence. Here, we report that iron-sulfur (Fe-S) clusters are critical targets of Cu toxicity in both Saccharomyces cerevisiae and C. neoformans in a manner that depends on the accessibility of Cu to the Fe-S cofactor. To respond to this Cu-dependent Fe-S stress, C. neoformans induces the transcription of mitochondrial ABC transporter Atm1, which functions in cytosolic-nuclear Fe-S protein biogenesis in response to Cu and in a manner dependent on the Cu metalloregulatory transcription factor Cuf1. As Atm1 functions in exporting an Fe-S precursor from the mitochondrial matrix to the cytosol, C. neoformans cells depleted for Atm1 are sensitive to Cu even while the Cu-detoxifying metallothionein proteins are highly expressed. We provide evidence for a previously unrecognized microbial defense mechanism to deal with Cu toxicity, and we highlight the importance for C. neoformans of having several distinct mechanisms for coping with Cu toxicity which together could contribute to the success of this microbe as an opportunistic human fungal pathogen. IMPORTANCE C. neoformans is an opportunistic pathogen that causes lethal meningitis in over 650,000 people annually. The severity of C. neoformans infections is further compounded by the use of toxic or poorly effective systemic antifungal agents as well as by the difficulty of diagnosis. Cu is a natural potent antimicrobial agent that is compartmentalized within the macrophage phagosome and used by innate immune cells to neutralize microbial pathogens. While the Cu detoxification machinery of C. neoformans is essential for virulence, little is known about the mechanisms by which Cu kills fungi. Here we report that Fe-S cluster-containing proteins, including members of the Fe-S protein biogenesis machinery itself, are critical targets of Cu toxicity and therefore that this biosynthetic process provides an important layer of defense against high Cu levels. Given the role of Cu ionophores as antimicrobials, understanding how Cu is toxic to microorganisms could lead to the development of effective, broad-spectrum antimicrobials. Moreover, understanding Cu toxicity could provide additional insights into the pathophysiology of human diseases of Cu overload such as Wilson's disease. Copyright © 2017 Garcia-Santamarina et al.

Endogenous Cryptococcus neoformans endophthalmitis with subretinal abscess in a HIV-infected man.

PubMed

Joseph, Joveeta; Sharma, Savitri; Narayanan, Raja

2018-07-01

To report a rare case of Cryptococcus neoformans endogenous endophthalmitis with subretinal abscess in a 36-year-old HIV-positive man, referred with progressive blurred vision in his right eye for the last 6 months. Vitreous biopsy followed by intravitreal ganciclovir did not result in significant improvement. Microbiology revealed the presence of C. neoformans, and intravitreal amphotericin B was then administered. The patient was treated aggressively with systemic and intravitreal antifungals but had a poor visual and anatomical outcome. A high degree of clinical suspicion combined with microbiological evaluation helped to arrive at an appropriate diagnosis.

Persistence of Pigment Production by Yeast Isolates Grown on CHROMagar Candida Medium

PubMed Central

Hospenthal, Duane R.; Murray, Clinton K.; Beckius, Miriam L.; Green, Judith A.; Dooley, David P.

2002-01-01

We evaluated the persistence of pigmentation in yeast isolates grown on the chromogenic medium CHROMagar Candida over 7 days. Candida, Cryptococcus, and Trichosporon isolates were inoculated alone or mixed onto duplicate sets of plates and incubated at 30 and 35°C. Candida albicans and Candida krusei were readily identified throughout the reading period, but Candida glabrata was difficult to differentiate from other species until the 3- or 4-day time point. Candida tropicalis produced colonies similar to those of rare Cryptococcus and Trichosporon species, and mixed cultures were often difficult to identify as such. PMID:12454192

Cryptococcal osteomyelitis: a report of 5 cases and a review of the recent literature.

PubMed

Medaris, Leigh Ann; Ponce, Brent; Hyde, Zane; Delgado, Dennis; Ennis, David; Lapidus, William; Larrison, Matthew; Pappas, Peter G

2016-06-01

Cryptococcus neoformans is a fungal pathogen associated with advanced HIV disease and other disorders associated with immune dysfunction. The pulmonary and the central nervous system are the most common manifestations of the disease. Localised osteomyelitis as the sole manifestation of extrapulmonary disease is rare. Herein, we present five cases of Cryptococcus osteomyelitis as the only manifestation of extrapulmonary disease. We also identified 84 additional cases of isolated cryptococcal osteomyelitis in the literature. Using these data, we have made some general recommendations regarding an approach to treatment of this uncommon clinical entity. © 2016 Blackwell Verlag GmbH.

Cryptococcus friedmannii, a new species of yeast from the Antarctic

NASA Technical Reports Server (NTRS)

Vishniac, H. S.

1985-01-01

Cryptococcus friedmannii Vishniac sp. nov. from an Antarctic cryptoendolithic community is a psychrophilic basidioblastomycete characterized by cream-colored colonies of cells with smooth, layered walls, budding monopolarly, producing amylose and extracellular proteinase, utilizing nitrate and D-alanine (inter alia) as nitrogen sources and L-arabinose, arbutin, cellobiose, D-glucuronate, maltose, melezitose, salicin, soluble starch, trehalose, and D-xylose as carbon sources. This species differs from all other basidiomycetous yeasts in possessing the following combination of characters: amylose production (positive), assimilation of cellobiose (positive), D-galactose (negative), myo-inositol (negative), D-mannitol (negative), and sucrose (negative).

In vitro effects of ambroxol on Cryptococcus adherence, planktonic cells, and biofilms.

PubMed

Kong, Qingtao; Du, Xue; Huang, Suyang; Yang, Rui; Zhang, Chengzhen; Shen, Yongnian; Liu, Weida; Sang, Hong

2017-07-01

The antifungal effects of ambroxol (Amb; the metabolite VIII of bromhexine) against Cryptococcus planktonic cells and mature biofilms were investigated in this study. Amb showed antifungal activity against planktonic cells and mature biofilms. Disk diffusion test similarly showed antifungal profile for planktonic cells. Furthermore, Amb was found to be synergetic with fluconazole against planktonic cells and reduced the adherence of cells to polystyrene. Our results suggest that Amb can inhibit cryptococcal cells and biofilms, indicating its potential role in the prevention and treatment of cryptococcosis. © 2017 APMIS. Published by John Wiley & Sons Ltd.

Bioactive terpenes from marine-derived fungi.

PubMed

Elissawy, Ahmed M; El-Shazly, Mohamed; Ebada, Sherif S; Singab, AbdelNasser B; Proksch, Peter

2015-04-03

Marine-derived fungi continue to be a prolific source of secondary metabolites showing diverse bioactivities. Terpenoids from marine-derived fungi exhibit wide structural diversity including numerous compounds with pronounced biological activities. In this review, we survey the last five years' reports on terpenoidal metabolites from marine-derived fungi with particular attention on those showing marked biological activities.

42 CFR 73.1 - Definitions.

Code of Federal Regulations, 2010 CFR

2010-10-01

... (including, but not limited to, bacteria, viruses, fungi, rickettsiae, or protozoa), or infectious substance... product of plants, animals, microorganisms (including, but not limited to, bacteria, viruses, fungi...

42 CFR 73.1 - Definitions.

Code of Federal Regulations, 2011 CFR

2011-10-01

... (including, but not limited to, bacteria, viruses, fungi, rickettsiae, or protozoa), or infectious substance... product of plants, animals, microorganisms (including, but not limited to, bacteria, viruses, fungi...

42 CFR 73.1 - Definitions.

Code of Federal Regulations, 2012 CFR

2012-10-01

... (including, but not limited to, bacteria, viruses, fungi, rickettsiae, or protozoa), or infectious substance... product of plants, animals, microorganisms (including, but not limited to, bacteria, viruses, fungi...

Clinical and microbiological characteristics of cryptococcosis in Singapore: predominance of Cryptococcus neoformans compared with Cryptococcus gattii.

PubMed

Chan, Monica; Lye, David; Win, Mar Kyaw; Chow, Angela; Barkham, Tim

2014-09-01

To describe the clinical features, treatments, outcomes, and subtype prevalence of cryptococcosis in Singapore. All patients with laboratory confirmed cryptococcal infections admitted from 1999 to 2007 to a teaching hospital in Singapore were reviewed retrospectively. Identification and molecular types of Cryptococcus neoformans variants and Cryptococcus gattii were determined by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Serotypes were inferred with a multiplex PCR method. Of 62 patients with cryptococcosis, C. neoformans var. grubii was the predominant subtype (in 95%), affecting mainly immunocompromised hosts (91%) with HIV infection (80%). Patients with HIV were younger (median age 36.5 vs. 49.5 years, p=0.006) and less likely to present with an altered mental status (14% vs. 50%, p=0.013). In contrast, delayed treatment (median 7 days vs. 2 days, p=0.03), pulmonary involvement (58% vs. 14%, p=0.03), and initial treatment with fluconazole (25% vs. 2%, p=0.02) were more common in HIV-negative patients. C. gattii was uncommon, affecting only three patients, all of whom were immunocompetent and had disseminated disease with pulmonary and neurological involvement. All C. gattii were RFLP type VG II, serotype B and all C. neoformans var. grubii were RFLP type VN I, serotype A, except for one that was RFLP type VN II. C. neoformans var. grubii, subtype VN I, was the predominant subtype in Singapore, infecting younger, mainly immunocompromised hosts with HIV. C. gattii was uncommon, causing pulmonary manifestations in older, immunocompetent patients and were RFLP type VG II. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

Photodynamic therapy can kill Cryptococcus neoformans in in vitro and in vivo models

NASA Astrophysics Data System (ADS)

Prates, Renato A.; da Silva, Eriques G.; Chaves, Priscila F.; Santos, Antônio José S.; Paula, Claudete R.; Ribeiro, Martha S.

2009-02-01

Cryptococcosis is an infection caused by the encapsulated yeast Cryptococcus neoformans and the most afflicted sites are lung, skin and central nervous system. A range of studies had reported that photodynamic therapy (PDT) can inactivate yeast cells; however, the in vivo experimental models of cryptococcosis photoinactivation are not commonly reported. The aim of this study was to investigate the ability of methylene blue (MB) combined with a low-power red laser to inactivate Cryptococcus neoformans in in vitro and in vivo experimental models. To perform the in vitro study, suspension of Cryptococcus neoformans ATCC-90112 (106cfu/mL) was used. The light source was a laser (Photon Lase III, DMC, SÃ#o Carlos, Brazil) emitting at λ660nm with output power of 90mW for 6 and 9min of irradiation, resulting fluences at 108 and 162J/cm². As photosensitizer, 100μM MB was used. For the in vivo study, 10 BALB/c mice had the left paw inoculated with C. neoformans ATCC-90112 (107cfu). Twenty-four hours after inoculation, PDT was performed using 150μM MB and 100mW red laser with fluence at 180J/cm2. PDT was efficient in vitro against C. neoformans in both parameters used: 3 log reduction with 108J/cm² and 6 log reduction with 162J/cm². In the in vivo experiment, PDT was also effective; however, its effect was less expressive than in the in vitro study (about 1 log reduction). In conclusion, PDT seems to be a helpful alternative to treat dermal cryptococcosis; however, more effective parameters must be found in in vivo studies.

Divalent Metal Cations Potentiate the Predatory Capacity of Amoeba for Cryptococcus neoformans.

PubMed

Fu, Man Shun; Casadevall, Arturo

2018-02-01

Among the best-studied interactions between soil phagocytic predators and a human-pathogenic fungus is that of Acanthamoeba castellanii and Cryptococcus neoformans The experimental conditions used in amoeba-fungus confrontation assays can have major effects on whether the fungus or the protozoan is ascendant in the interaction. In the presence of Mg 2+ and Ca 2+ in phosphate-buffered saline (PBS), C. neoformans was consistently killed when incubated with A. castellanii A. castellanii survived better in the presence of Mg 2+ and Ca 2+ , even when incubated with C. neoformans In the absence of Mg 2+ and Ca 2+ , C. neoformans survived when incubated with A. castellanii , and the percentage of dead amoebae was higher than when incubated without yeast cells. These results show that the presence of Mg 2+ and Ca 2+ can make a decisive contribution toward tilting the outcome of the interaction in favor of the amoeba. Of the two metals, Mg 2+ had a stronger effect than Ca 2+ The cations enhanced A. castellanii activity against C. neoformans via enhanced phagocytosis, which is the major mechanism by which amoebae kill fungal cells. We found no evidence that amoebae use extracellular killing mechanisms in their interactions with C. neoformans In summary, the presence of Mg 2+ and Ca 2+ enhanced the cell adhesion on the surfaces and the motility of the amoeba, thus increasing the chance for contact with C. neoformans and the frequency of phagocytosis. Our findings imply that the divalent cation concentration in soils could be an important variable for whether amoebae can control C. neoformans in the environment. IMPORTANCE The grazing of soil organisms by phagocytic predators such as amoebae is thought to select for traits that enable some of them to acquire the capacity for virulence in animals. Consequently, knowledge about the interactions between amoebae and soil microbes, such as pathogenic fungi, is important for understanding how virulence can emerge. We show that the interaction between an amoeba and the pathogenic fungus C. neoformans is influenced by the presence in the assay of magnesium and calcium, which potentiate amoebae. The results may also have practical applications, since enriching soils with divalent cations may reduce C. neoformans numbers in contaminated soils. Copyright © 2018 American Society for Microbiology.

Antimicrobial activity of Schinus lentiscifolius (Anacardiaceae).

PubMed

Gehrke, Ilaine T S; Neto, Alexandre T; Pedroso, Marcelo; Mostardeiro, Clarice P; Da Cruz, Ivana B M; Silva, Ubiratan F; Ilha, Vinicius; Dalcol, Ionara I; Morel, Ademir F

2013-07-09

Schinus lentiscifolius Marchand (syn. Schinus weinmannifolius Engl) is a plant native to Rio Grande do Sul (Southern Brazil) and has been used in Brazilian traditional medicine as antiseptic and antimicrobial for the treatment of many different health problems as well as to treat leucorrhea and to assist in ulcer and wound healing. Although it is a plant widely used by the population, there are no studies proving this popular use. The crude aqueous extract, the crude neutral methanol extract, fractions prepared from this extract (n-hexane, ethyl acetate, and n-butanol), pure compounds isolated from these fractions, and derivatives were investigated in vitro for antimicrobial activities against five Gram positive bacteria: Bacillus subtilis, Staphylococcus aureus, Staphylococcus epidermidis, Staphylococcus saprophyticus, Streptococcus pyogenes, three Gram negative bacteria: Escherichia coli, Pseudomonas aeruginosa, and Shigella sonnei, and four yeasts: Candida albicans, Candida tropicalis, Cryptococcus neoformans, and Saccharomyces cerevisiae. The isolated compound moronic acid, which is the most active, was tested against a range of other bacteria such as two Gram positive bacteria, namely, Bacillus cereus, Enterococcus spp, and six Gram negative bacteria, namely, Burkholderia cepacia, Providencia stuartii, Morganella morganii, Enterobacter cloacae, Enterobacter aerogenes, and Proteus mirabilis. The leaf aqueous extract (decoction) of Schinus lentiscifolius showed a broad spectrum of antibacterial activity, ranging from 125 to 250 μg/ml (MIC) against the tested bacteria and fungi. The n-hexane extract, despite being very little active against bacteria, showed an excellent antifungal activity, especially against Candida albicans (MIC=25 μg/ml), Candida tropicalis (MIC=15.5 μg/ml), and Cryptococcus neoformans, (MIC=15.5 μg/ml). From the acetate fraction (the most active against bacteria), compounds 1-6 were isolated: nonadecanol (1), moronic acid (2), gallic acid methyl ester (3), gallic acid (4), quercetin (5) and quercitrin (6). The minimal inhibitory concentration (MIC) of moronic acid between 1.5 and 3 μg/ml against most of the tested bacteria shows that it is one of the metabolites responsible for the antibacterial activity of Schinus lentiscifolius. The antimicrobial activity and some constituents of Schinus lentiscifolius are reported for the first time. The results of the present study provide scientific basis for the popular use of Schinus lentiscifolius for a number of different health problems. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Molecular genetics of lignin-degrading fungi and their applications in organopollutant degradation

Treesearch

Daniel Cullen

2002-01-01

This chapter provides an overview of the physiology and associated molecular genetics of wood- decaying fungi as they relate to organopollutant degradation. White-rot fungi are characterized by an ability to fragment all major structural polymers of wood including lignin. More poorly understood are the brown-rot fungi, which rapidly depolymerize cellulosic materials...

A Unique Fungal Two-Component System Regulates Stress Responses, Drug Sensitivity, Sexual Development, and Virulence of Cryptococcus neoformans

PubMed Central

Bahn, Yong-Sun; Kojima, Kaihei; Cox, Gary M.

2006-01-01

The stress-activated mitogen-activated protein kinase (MAPK) pathway is widely used by eukaryotic organisms as a central conduit via which cellular responses to the environment effect growth and differentiation. The basidiomycetous human fungal pathogen Cryptococcus neoformans uniquely uses the stress-activated Pbs2-Hog1 MAPK system to govern a plethora of cellular events, including stress responses, drug sensitivity, sexual reproduction, and virulence. Here, we characterized a fungal “two-component” system that controls these fundamental cellular functions via the Pbs2-Hog1 MAPK cascade. A typical response regulator, Ssk1, modulated all Hog1-dependent phenotypes by controlling Hog1 phosphorylation, indicating that Ssk1 is the major upstream signaling component of the Pbs2-Hog1 pathway. A second response regulator, Skn7, governs sensitivity to Na+ ions and the antifungal agent fludioxonil, negatively controls melanin production, and functions independently of Hog1 regulation. To control these response regulators, C. neoformans uses multiple sensor kinases, including two-component–like (Tco) 1 and Tco2. Tco1 and Tco2 play shared and distinct roles in stress responses and drug sensitivity through the Hog1 MAPK system. Furthermore, each sensor kinase mediates unique cellular functions for virulence and morphological differentiation. Our findings highlight unique adaptations of this global two-component MAPK signaling cascade in a ubiquitous human fungal pathogen. PMID:16672377

Cryptococcus: from environmental saprophyte to global pathogen

PubMed Central

May, Robin C.; Stone, Neil R.H.; Wiesner, Darin L.; Bicanic, Tihana; Nielsen, Kirsten

2016-01-01

Cryptococcosis is a globally distributed invasive fungal infection that is caused by species within the genus Cryptococcus which presents substantial therapeutic challenges. Although natural human-to-human transmission has never been observed, recent work has identified multiple virulence mechanisms that enable cryptococci to infect, disseminate within and ultimately kill their human host. In this Review, we describe these recent discoveries that illustrate the intricacy of host-pathogen interactions and reveal new details about the host immune responses that either help to protect against disease or increase host susceptibility. In addition, we discuss how this improved understanding of both the host and the pathogen informs potential new avenues for therapeutic development. PMID:26685750

Cryptococcus: from environmental saprophyte to global pathogen.

PubMed

May, Robin C; Stone, Neil R H; Wiesner, Darin L; Bicanic, Tihana; Nielsen, Kirsten

2016-02-01

Cryptococcosis is a globally distributed invasive fungal infection that is caused by species within the genus Cryptococcus which presents substantial therapeutic challenges. Although natural human-to-human transmission has never been observed, recent work has identified multiple virulence mechanisms that enable cryptococci to infect, disseminate within and ultimately kill their human host. In this Review, we describe these recent discoveries that illustrate the intricacy of host-pathogen interactions and reveal new details about the host immune responses that either help to protect against disease or increase host susceptibility. In addition, we discuss how this improved understanding of both the host and the pathogen informs potential new avenues for therapeutic development.

Dual Candida albicans and Cryptococcus neoformans fungaemia in an AIDS presenter: a unique disease association in the highly active antiretroviral therapy (HAART) era.

PubMed

Manfredi, Roberto; Calza, Leonardo; Chiodo, Francesco

2002-12-01

A case report of a patient who discovered his HIV infection concurrently with an advanced immunodeficiency and a dual Candida albicans and Cryptococcus neoformans fungaemia is discussed with reference to the changing epidemiology and clinical features of HIV infection and AIDS in the highly active antiretroviral therapy (HAART) era. The tendency to develop multiple concomitant AIDS-defining illnesses at the time of first hospitalisation seems to be an increasing feature in patients who remain unaware of or neglect their HIV disease and who are still at risk of opportunist infections even with the availability of HAART.

Role of Sterylglucosidase 1 (Sgl1) on the pathogenicity of Cryptococcus neoformans: potential applications for vaccine development

PubMed Central

Rella, Antonella; Mor, Visesato; Farnoud, Amir M.; Singh, Ashutosh; Shamseddine, Achraf A.; Ivanova, Elitza; Carpino, Nicholas; Montagna, Maria T.; Luberto, Chiara; Del Poeta, Maurizio

2015-01-01

Cryptococcosis caused by Cryptococcus neoformans and Cryptococcus gattii affects a large population and is a cause of significant morbidity and mortality. Despite its public health burden, there are currently no vaccines against cryptococcosis and new strategies against such infections are needed. In this study, we demonstrate that C. neoformans has the biochemical ability to metabolize sterylglucosides (SGs), a class of immunomodulatory glycolipids. Genetic manipulations that eliminate cryptococccal sterylglucosidase lead to the accumulation of SGs and generate a mutant strain (Δsgl1) that is non-pathogenic in the mouse models of cryptococcosis. Interestingly, this mutant strain acts as a vaccine strain and protects mice against cryptococcosis following infection with C. neoformans or C. gattii. The immunity induced by the Δsgl1 strain is not CD4+ T-cells dependent. Immunocompromised mice, which lack CD4+ T-cells, are able to control the infection by Δsgl1 and acquire immunity against the challenge by wild-type C. neoformans following vaccination with the Δsgl1 strain. These findings are particularly important in the context of HIV/AIDS immune deficiency and suggest that the Δsgl1 strain might provide a potential vaccination strategy against cryptococcosis. PMID:26322039

Role of Sterylglucosidase 1 (Sgl1) on the pathogenicity of Cryptococcus neoformans: potential applications for vaccine development.

PubMed

Rella, Antonella; Mor, Visesato; Farnoud, Amir M; Singh, Ashutosh; Shamseddine, Achraf A; Ivanova, Elitza; Carpino, Nicholas; Montagna, Maria T; Luberto, Chiara; Del Poeta, Maurizio

2015-01-01

Cryptococcosis caused by Cryptococcus neoformans and Cryptococcus gattii affects a large population and is a cause of significant morbidity and mortality. Despite its public health burden, there are currently no vaccines against cryptococcosis and new strategies against such infections are needed. In this study, we demonstrate that C. neoformans has the biochemical ability to metabolize sterylglucosides (SGs), a class of immunomodulatory glycolipids. Genetic manipulations that eliminate cryptococccal sterylglucosidase lead to the accumulation of SGs and generate a mutant strain (Δsgl1) that is non-pathogenic in the mouse models of cryptococcosis. Interestingly, this mutant strain acts as a vaccine strain and protects mice against cryptococcosis following infection with C. neoformans or C. gattii. The immunity induced by the Δsgl1 strain is not CD4(+) T-cells dependent. Immunocompromised mice, which lack CD4(+) T-cells, are able to control the infection by Δsgl1 and acquire immunity against the challenge by wild-type C. neoformans following vaccination with the Δsgl1 strain. These findings are particularly important in the context of HIV/AIDS immune deficiency and suggest that the Δsgl1 strain might provide a potential vaccination strategy against cryptococcosis.

Skin testing of guinea pigs and footpad testing of mice with a new antigen for detecting delayed hypersensitivity to Cryptococcus neoformans.

PubMed

Murphy, J W; Gregory, J A; Larsh, H W

1974-02-01

This study was undertaken to evaluate the potential of a cryptococcal culture filtrate antigen, cryptococcin C184, for detecting delayed hypersensitivity in Cryptococcus neoformans-injected animals. The antigen was tested on guinea pigs which had received saline or C. neoformans and on animals sensitized to Histoplasma capsulatum, Blastomyces dermatitidis, Candida albicans, or Sporothrix schenckii. A delayed-type hypersensitivity response was elicited by cryptococcin C184 in C. neoformans-injected guinea pigs, whereas no indurations or erythemas were seen at 48 h after skin testing of saline controls or heterologously sensitized guinea pigs. Besides being specific for Cryptococcus, the antigen showed a high degree of sensitivity and was reproducible. Footpad tests were conducted with the antigen on mice which had previously received either 10(5) viable C. neoformans cells or saline. Delayed hypersensitivity was indicated in the C. neoformans-injected mice by the increase in thickness of antigen-injected footpads when compared with the saline-injected footpads. In control mice, antigen- and saline-injected footpads were comparable in thickness 24 h after injection. Mice sensitized to B. dermatitidis were footpad tested with C184, and no cross-reactivity was demonstrated.

Homology modeling, molecular docking and molecular dynamics studies of the catalytic domain of chitin deacetylase from Cryptococcus laurentii strain RY1.

PubMed

Sarkar, Soumyadev; Gupta, Suchetana; Chakraborty, Writachit; Senapati, Sanjib; Gachhui, Ratan

2017-11-01

This study provides structural insights into chitin deacetylase, over-expressing under nitrogen limiting condition in Cryptococcus laurentii strain RY1. The enzyme converts chitin, the second most abundant natural biopolymer, to chitosan, which offers tremendous applications in diverse fields. To elucidate the structure-function relationship of this biologically and industrially important enzyme, a homology model of the catalytic domain was constructed. The stability of the structure was assessed by molecular dynamics simulation studies. Tryptophan 151 of the domain was identified to form hydrogen bond and stacking interaction with chitin upon docking. In Silico substitution of Tryptophan (W) to Alanine (A), Phenylalanine (F) and Aspartate (D) corroborated the importance of the Tryptophan residue in interaction with the substrate. This is the first report of unravelling the structural characteristics of chitin deacetylase from Cryptococcus and understanding the approach of the enzyme towards its substrate. Our results would be helpful to perform experimental validations and apply quantum mechanics/molecular mechanics techniques to determine the detailed catalytic mechanism and enhance the industrial potency of the enzyme. Copyright © 2017 Elsevier B.V. All rights reserved.

Ancestral state reconstruction infers phytopathogenic origins of sooty blotch and flyspeck fungi on apple.

PubMed

Ismail, Siti Izera; Batzer, Jean Carlson; Harrington, Thomas C; Crous, Pedro W; Lavrov, Dennis V; Li, Huanyu; Gleason, Mark L

2016-01-01

Members of the sooty blotch and flyspeck (SBFS) complex are epiphytic fungi in the Ascomycota that cause economically damaging blemishes of apples worldwide. SBFS fungi are polyphyletic, but approx. 96% of SBFS species are in the Capnodiales. Evolutionary origins of SBFS fungi remain unclear, so we attempted to infer their origins by means of ancestral state reconstruction on a phylogenetic tree built utilizing genes for the nuc 28S rDNA (approx. 830 bp from near the 59 end) and the second largest subunit of RNA polymerase II (RPB2). The analyzed taxa included the well-known genera of SBFS as well as non-SBFS fungi from seven families within the Capnodiales. The non-SBFS taxa were selected based on their distinct ecological niches, including plant-parasitic and saprophytic species. The phylogenetic analyses revealed that most SBFS species in the Capnodiales are closely related to plant-parasitic fungi. Ancestral state reconstruction provided strong evidence that plant-parasitic fungi were the ancestors of the major SBFS lineages. Knowledge gained from this study may help to better understand the ecology and evolution of epiphytic fungi. © 2016 by The Mycological Society of America.

Disarming Fungal Pathogens: Bacillus safensis Inhibits Virulence Factor Production and Biofilm Formation by Cryptococcus neoformans and Candida albicans

PubMed Central

2017-01-01

ABSTRACT Bacteria interact with each other in nature and often compete for limited nutrient and space resources. However, it is largely unknown whether and how bacteria also interact with human fungal pathogens naturally found in the environment. Here, we identified a soil bacterium, Bacillus safensis, which potently blocked several key Cryptococcus neoformans virulence factors, including formation of the antioxidant pigment melanin and production of the antiphagocytic polysaccharide capsule. The bacterium also inhibited de novo cryptococcal biofilm formation but had only modest inhibitory effects on already formed biofilms or planktonic cell growth. The inhibition of fungal melanization was dependent on direct cell contact and live bacteria. B. safensis also had anti-virulence factor activity against another major human-associated fungal pathogen, Candida albicans. Specifically, dual-species interaction studies revealed that the bacterium strongly inhibited C. albicans filamentation and biofilm formation. In particular, B. safensis physically attached to and degraded candidal filaments. Through genetic and phenotypic analyses, we demonstrated that bacterial chitinase activity against fungal cell wall chitin is a factor contributing to the antipathogen effect of B. safensis. PMID:28974618

Research advance on stable mechanism of endophytic fungi to red wine colour during the aging

NASA Astrophysics Data System (ADS)

Nan, Lijun; Li, Yashan; Cui, Changwei; Ning, Na; Huang, Jing; Xu, Chengdong; Tao, Fang; Zhang, Jinyong

2018-04-01

Based on the fact that persistent mutation of vinous color was not conducive to the stabilization of vinous quality during the aging, research advance on the stable mechanism of endophytic fungi to colour of red wine during the aging, including investigative status and developmental dynamic at home and abroad, endophytes and pigment of materials in wine, including effect of endophyte on vinaceous color, and even the application of tracer method in wine was summarized, respectively. The relationship between diversity of community the endophytic fungi and the main pigment material in wine was existent objectively, also included the response mechanism on colony dynamic of endophytic fungi to the various pigment as well as substance related to color, which laid the foundation for exploring the relationships between endophytic fungi and wine color, and the variational mechanism of the color under endophytic fungi during the aging period of wine. Color as an important reference index of wine quality influenced not only the sensory evaluation of consumer, but also the quality of wine because of the self-aggregation or combination of phenolic composition with other substances under the endophytic fungi during the storage. Only steady wine in the color could guarantee the security of quality.